[10920010] |<article>United States</article>
[10920020] |The '''United States of America''', usually referred to as the '''United States''', the '''U.S.''' or '''America''', is a [[constitutional republic|constitutional]] [[federal republic]] comprising [[U.S. state|fifty states]] and a [[federal district]], as well as [[Territories of the United States|several territories]], or [[insular area]]s, scattered around the [[Caribbean]] and Pacific.
[10920030] |The [[country]] is situated mostly in central [[North America]], where its [[Continental United States|forty-eight contiguous states]] and [[Washington, D.C.]], the capital district, lie between the [[Pacific Ocean|Pacific]] and [[Atlantic Ocean]]s, bordered by [[Canada]] to the [[Canada – United States border|north]] and [[Mexico]] to the [[United States–Mexico border|south]].
[10920040] |The state of [[Alaska]] is in the northwest of the continent, with Canada to its east and [[Russia]] to the west across the [[Bering Strait]], and the state of [[Hawaii]] is an [[archipelago]] in the mid-Pacific.
[10920050] |At 3.79 million square miles (9.83 million km²) and with more than 300 million people, the United States is the [[List of countries and outlying territories by total area|third or fourth]] largest country by total area, and third largest by land area and [[List of countries by population|by population]].
[10920060] |The United States is one of the world's most [[Multiculturalism|ethnically diverse]] nations, the product of large-scale [[immigration to the United States|immigration from many countries]].
[10920070] |The [[Economy of the United States|U.S. economy]] is the largest national economy in the world, with a nominal 2006 [[gross domestic product]] (GDP) of more than [[United States dollar|US$]]13 trillion (over 25% of the world total based on [[nominal GDP]] and almost 20% by [[purchasing power parity]]).
[10920080] |The nation was founded by [[Thirteen Colonies|thirteen colonies]] of [[Kingdom of Great Britain|Great Britain]] located along the [[East Coast of the United States|Atlantic seaboard]].
[10920090] |Proclaiming themselves "states," they issued the [[United States Declaration of Independence|Declaration of Independence]] on [[July 4]], [[1776]].
[10920100] |The rebellious states defeated Great Britain in the [[American Revolutionary War]], the first successful [[History of colonialism|colonial war of independence]].
[10920110] |A [[Philadelphia Convention|federal convention]] adopted the current [[United States Constitution]] on [[September 17]], [[1787]]; its ratification the following year made the states part of a single republic.
[10920120] |The [[United States Bill of Rights|Bill of Rights]], comprising ten [[List of amendments to the United States Constitution|constitutional amendments]], was ratified in 1791.
[10920130] |In the nineteenth century, the United States acquired land from [[Louisiana Purchase|France]], [[Adams-Onís Treaty|Spain]], the [[Oregon Country|United Kingdom]], [[Mexican-American War|Mexico]], and [[Alaska purchase|Russia]], and [[Texas Annexation|annexed]] the [[Republic of Texas]] and the [[Republic of Hawaii]].
[10920140] |Disputes between the [[Southern United States|agrarian South]] and [[Northern United States|industrial North]] over [[states' rights]] and the expansion of the [[slavery in the United States|institution of slavery]] provoked the [[American Civil War]] of the 1860s.
[10920150] |The North's victory prevented a permanent split of the country and led to the [[Thirteenth Amendment to the United States Constitution|end of legal slavery]] in the United States.
[10920160] |The [[Spanish-American War]] and [[World War I]] confirmed the nation's status as a military power.
[10920170] |In 1945, the United States emerged from [[World War II]] as the [[Nuclear weapons and the United States|first country with nuclear weapons]], a permanent member of the [[United Nations Security Council]], and a founding member of [[NATO]].
[10920180] |In the post–[[Cold War]] era, the United States is the only remaining [[superpower]]—accounting for [[List of countries by military expenditures|approximately 50% of global military spending]]—and a dominant economic, political, and cultural force in the world.
[10920190] |==Etymology== 
[10920200] |The term ''[[Americas#Naming|America]]'', for the lands of the [[Western Hemisphere|western hemisphere]], was coined in 1507 after [[Amerigo Vespucci]], an Italian explorer and cartographer.
[10920210] |The full name of the country was first used officially in the [[United States Declaration of Independence|Declaration of Independence]], which was the "unanimous Declaration of the thirteen united States of America" adopted by the "Representatives of the united States of America" on [[July 4]], [[1776]].
[10920220] |The current name was finalized on [[November 15]], [[1777]], when the [[Second Continental Congress]] adopted the [[Articles of Confederation]], the first of which states, "The Stile of this Confederacy shall be 'The United States of America.'"
[10920230] |Common short forms and abbreviations of the United States of America include the ''United States,'' the ''U.S.'', the ''U.S.A.'', and ''America''.
[10920240] |Colloquial names for the country include the ''U.S. of A.'' and ''the States''.
[10920250] |''[[Columbia (name)|Columbia]]'', a once popular name for the Americas and the United States, was derived from [[Christopher Columbus]].
[10920260] |It appears in the name "[[Washington, D.C.|District of Columbia]]".
[10920270] |A female personification of Columbia appears on some official documents, including certain prints of [[United States dollar|U.S. currency]].
[10920280] |The standard way to refer to a citizen of the United States is as an ''[[American (word)|American]].''
[10920290] |Though ''United States'' is the formal adjective, ''American'' and ''U.S.'' are the most common adjectives used to refer to the country ("American values," "U.S. forces").
[10920300] |''American'' is rarely used in English to refer to people not connected to the United States.
[10920310] |The phrase "the United States" was originally treated as plural—e.g, "the United States are"—including in the [[Thirteenth Amendment to the United States Constitution|Thirteenth Amendment]] to the Constitution, ratified in 1865.
[10920320] |However, it became increasingly common to treat the name as singular—e.g., "the United States is"—after the end of the Civil War.
[10920330] |The singular form is now standard, while the plural form is retained in the set idiom "these United States."
[10920340] |==Geography== 
[10920350] |The United States is situated almost entirely in the [[Western Hemisphere|western hemisphere]]: the [[continental United States|contiguous United States]] stretches from the [[Pacific Ocean|Pacific]] on the west to the [[Atlantic Ocean|Atlantic]] on the east, with the [[Gulf of Mexico]] to the southeast, and bordered by [[Canada]] on the north and [[Mexico]] on the south.
[10920360] |[[Alaska]] is the largest state in area; separated from the contiguous U.S. by Canada, it touches the Pacific on the south and [[Arctic Ocean]] on the north.
[10920370] |[[Hawaii]] occupies an [[archipelago]] in the central Pacific, southwest of North America.
[10920380] |The United States is the world's third or fourth [[List of countries and outlying territories by total area|largest nation by total area]], before or after [[People's Republic of China|China]].
[10920390] |The ranking varies depending on (a) how two territories disputed by China and [[India]] are counted and (b) how the total size of the United States is calculated: the CIA ''World Factbook'' gives , the United Nations Statistics Division gives , and the ''Encyclopedia Britannica'' gives .
[10920400] |Including only land area, the United States is third in size behind Russia and China, just ahead of Canada.
[10920410] |The United States also possesses several [[Territories of the United States|insular territories]] scattered around the [[Caribbean|West Indies]] (e.g., the [[Commonwealth (United States insular area)|commonwealth]] of [[Puerto Rico]]) and the Pacific (e.g., [[Guam]]).
[10920420] |The coastal plain of the Atlantic seaboard gives way further inland to [[deciduous]] forests and the rolling hills of the [[Piedmont (United States)|Piedmont]].
[10920430] |The [[Appalachian Mountains]] divide the eastern seaboard from the [[Great Lakes]] and the grasslands of the [[Midwestern United States|Midwest]].
[10920440] |The [[Mississippi River|Mississippi]]&ndash;[[Missouri River]], the world's [[List of rivers by length|fourth longest river system]], runs mainly north-south through the heart of the country.
[10920450] |The flat, fertile prairie land of the [[Great Plains]] stretches to the west, interrupted by [[U.S. Interior Highlands|a highland region]] along its southeastern portion.
[10920460] |The [[Rocky Mountains]], at the western edge of the Great Plains, extend north to south across the continental United States, reaching altitudes higher than 14,000&nbsp;feet (4,300&nbsp;m) in [[Colorado]].
[10920470] |The area to the west of the Rocky Mountains is dominated by the rocky [[Great Basin]] and deserts such as the [[Mojave Desert|Mojave]].
[10920480] |The [[Sierra Nevada (U.S.)|Sierra Nevada]] range runs parallel to the Rockies, relatively close to the [[West Coast of the United States|Pacific coast]].
[10920490] |At 20,320&nbsp;feet (6,194&nbsp;m), Alaska's [[Mount McKinley]] is the country's tallest peak.
[10920500] |Active [[volcano]]es are common throughout the [[Alexander Archipelago|Alexander]] and [[Aleutian Islands]], and the entire state of Hawaii is built upon tropical volcanic islands.
[10920510] |The [[supervolcano]] underlying [[Yellowstone National Park]] in the Rockies is the continent's largest volcanic feature.
[10920520] |Because of the United States' large size and wide range of geographic features, nearly every type of [[climate]] is represented.
[10920530] |The climate is [[temperate]] in most areas, [[Tropics|tropical]] in Hawaii and southern [[Florida]], [[Polar climate|polar]] in Alaska, [[Semi-arid climate|semi-arid]] in the Great Plains west of the [[100th meridian west|100th meridian]], desert in the Southwest, [[Mediterranean climate|Mediterranean]] in [[Coastal California]], and [[arid]] in the Great Basin.
[10920540] |Extreme weather is not uncommon—the states bordering the [[Gulf of Mexico]] are prone to [[hurricane]]s, and most of the world's [[tornado]]es occur within the continental United States, primarily in the Midwest's [[Tornado Alley]].
[10920550] |==Environment== 
[10920560] |U.S. plant life is very diverse; the country has more than 17,000 identified native species of [[flora]].
[10920570] |More than 400 mammal, 700 bird, 500 reptile and amphibian, and 90,000 insect species have been documented.
[10920580] |The [[Endangered Species Act]] of 1973 protects threatened and endangered species and their habitats, which are monitored by the [[United States Fish and Wildlife Service|U.S. Fish and Wildlife Service]].
[10920590] |The U.S. has fifty-eight [[List of areas in the United States National Park System|national parks]] and hundreds of other federally managed parks, forests, and [[wilderness area]]s.
[10920600] |Altogether, the U.S. government regulates 28.8% of the country's total land area.
[10920610] |Most such public land comprises protected parks and forestland, though some federal land is leased for oil and gas drilling, mining, or cattle ranching.
[10920620] |The [[energy policy of the United States]] is widely debated; many call on the country to take a leading role in fighting [[global warming]].
[10920630] |The United States is currently the second largest emitter, after the People's Republic of China, of [[carbon dioxide]] from the burning of [[fossil fuel]]s.
[10920640] |==History== 
[10920650] |===Native Americans and European settlers=== 
[10920660] |The [[Indigenous peoples of the Americas|indigenous peoples]] of the U.S. mainland, including [[Alaska Natives]], are thought to have [[Models of migration to the New World|migrated from Asia]].
[10920670] |They began arriving at least 12,000 and as many as 40,000 years ago.
[10920680] |Several indigenous communities in the [[pre-Columbian]] era developed advanced agriculture, grand architecture, and state-level societies.
[10920690] |In 1492, Genoese explorer [[Christopher Columbus]], under contract to the Spanish crown, reached several Caribbean islands, making [[First contact (anthropology)|first contact]] with the indigenous population.
[10920700] |In the years that followed, the majority of the indigenous American peoples were killed by epidemics of [[Eurasia]]n diseases.
[10920710] |On [[April 2]], [[1513]], Spanish [[conquistador]] [[Juan Ponce de León]] landed on what he called "[[History of Florida|La Florida]]"—the first documented European arrival on what would become the U.S. mainland.
[10920720] |Of the colonies Spain established in the region, only [[St. Augustine, Florida|St. Augustine]], founded in 1565, remains.
[10920730] |Later Spanish settlements in the present-day [[southwestern United States]] drew thousands through Mexico.
[10920740] |French [[fur trade]]rs established outposts of [[New France]] around the [[Great Lakes]]; France eventually claimed much of the North American interior as far south as the Gulf of Mexico.
[10920750] |The first successful English settlements were the [[Colony of Virginia|Virginia Colony]] in [[Jamestown, Virginia|Jamestown]] in 1607 and the [[Pilgrim]]s' [[Plymouth Colony]] in 1620.
[10920760] |The 1628 chartering of the [[Massachusetts Bay Colony]] resulted in a wave of migration; by 1634, [[New England]] had been settled by some 10,000 [[Puritan]]s.
[10920770] |Between the late 1610s and the American Revolution, an estimated 50,000 convicts were shipped to England's, and later Great Britain's, American colonies.
[10920780] |Beginning in 1614, the Dutch established settlements along the lower [[Hudson River]], including [[New Amsterdam]] on [[Manhattan|Manhattan Island]].
[10920790] |The small settlement of [[New Sweden]], founded along the [[Delaware River]] in 1638, was taken over by the Dutch in 1655.
[10920800] |By 1674, English forces had won the former Dutch colonies in the [[Anglo-Dutch Wars|Anglo–Dutch Wars]]; the province of [[New Netherland]] was renamed [[New York]].
[10920810] |Many new immigrants, especially to [[History of the Southern United States|the South]], were [[indentured servants]]—some two-thirds of all Virginia immigrants between 1630 and 1680.
[10920820] |By the turn of the century, [[Slavery in the colonial United States|African slaves]] were becoming the primary source of bonded labor.
[10920830] |With the 1729 division of [[the Carolinas]] and the 1732 colonization of [[Georgia (U.S. state)|Georgia]], the thirteen British colonies that would become the United States of America were established.
[10920840] |All had active local and colonial governments with elections open to most free men, with a growing devotion to the ancient [[rights of Englishmen]] and a sense of self government that stimulated support for [[republicanism]].
[10920850] |All had legalized the [[African slave trade]].
[10920860] |With high birth rates, low death rates, and steady immigration, the colonies doubled in population every twenty-five years.
[10920870] |The Christian [[Revivalism|revivalist]] movement of the 1730s and 1740s known as the [[First Great Awakening|Great Awakening]] fueled interest in both religion and religious liberty.
[10920880] |In the [[French and Indian War]], British forces seized Canada from the French, but the [[francophone]] population remained politically isolated from the southern colonies.
[10920890] |By 1770, those thirteen colonies had an increasingly [[Anglicisation|Anglicized]] population of three million, approximately half that of Britain.
[10920900] |Though [[No taxation without representation|subject to British taxation]], they were given no representation in the [[Parliament of Great Britain]].
[10920910] |===Independence and expansion=== 
[10920920] |Tensions between American colonials and the British during the [[American Revolution|revolutionary period]] of the 1760s and early 1770s led to the [[American Revolutionary War]], fought from 1775 through 1781.
[10920930] |On [[June 14]], [[1775]], the [[Second Continental Congress|Continental Congress]], convening in [[Philadelphia]], established a [[Continental Army]] under the command of [[George Washington]].
[10920940] |Proclaiming that "[[all men are created equal]]" and endowed with "certain [[inalienable rights|unalienable Rights]]," the Congress adopted the [[United States Declaration of Independence|Declaration of Independence]] on [[July 4]], [[1776]].
[10920950] |The Declaration, drafted largely by [[Thomas Jefferson]], pronounced the colonies [[sovereignty|sovereign]] "[[state]]s.
[10920960] |" In 1777, the [[Articles of Confederation]] were adopted, uniting the states under a weak federal government that operated until 1788.
[10920970] |Some 70,000–80,000 [[Loyalist (American Revolution)|loyalists]] to the British Crown fled the rebellious states, many to [[Nova Scotia]] and the new [[Canada under British Imperial control (1764-1867)|British holdings in Canada]].
[10920980] |Native Americans, with divided allegiances, fought on both sides of [[Western theater of the American Revolutionary War|the war's western front]].
[10920990] |After the [[Siege of Yorktown|defeat of the British army]] by American forces who were [[France in the American Revolutionary War|assisted by the French]], Great Britain [[Treaty of Paris (1783)|recognized the sovereignty]] of the thirteen states in 1783.
[10921000] |A [[Philadelphia Convention|constitutional convention]] was organized in 1787 by those who wished to establish a strong national government with power over the states.
[10921010] |By June 1788, nine states had ratified the [[United States Constitution]], sufficient to establish the new government; the republic's [[1st United States Congress|first Senate, House of Representatives]], and [[President of the United States|president]]—George Washington—took office in 1789.
[10921020] |[[New York City]] was the federal capital for a year, before the government relocated to Philadelphia.
[10921030] |In 1791, the states ratified the [[United States Bill of Rights|Bill of Rights]], ten amendments to the Constitution forbidding federal restriction of personal freedoms and guaranteeing a range of legal protections.
[10921040] |Attitudes toward [[Slavery in the United States|slavery]] were shifting; a [[Article One of the United States Constitution#Section 9: Limits on Congress|clause in the Constitution]] protected the African slave trade only until 1808.
[10921050] |The Northern states abolished slavery between 1780 and 1804, leaving the [[slave state]]s of the South as defenders of the "[[peculiar institution]]."
[10921060] |In 1800, the federal government moved to the newly founded [[History of Washington, D.C.|Washington, D.C.]] The [[Second Great Awakening]] made [[evangelicalism]] a force behind various social [[reform movement]]s.
[10921070] |Americans' eagerness to [[Territorial acquisitions of the United States|expand westward]] began a cycle of [[Indian Wars]] that stretched to the end of the nineteenth century, as Native Americans were stripped of their land.
[10921080] |The [[Louisiana Purchase]] of French-claimed territory under President Thomas Jefferson in 1803 virtually doubled the nation's size.
[10921090] |The [[War of 1812]], declared against Britain over various grievances and fought to a draw, strengthened American [[nationalism]].
[10921100] |A series of U.S. military incursions into Florida led [[Spanish Cession|Spain to cede]] it and other Gulf Coast territory in 1819.
[10921110] |The country annexed the [[Republic of Texas]] in 1845.
[10921120] |The concept of [[Manifest Destiny]] was popularized during this time.
[10921130] |The 1846 [[Oregon Treaty]] with Britain led to U.S. control of the present-day [[Northwestern United States|American Northwest]].
[10921140] |The U.S. victory in the [[Mexican-American War]] resulted in the 1848 [[Mexican Cession|cession]] of [[California]] and much of the present-day [[Southwestern United States|American Southwest]].
[10921150] |The [[California Gold Rush]] of 1848–49 further spurred western migration.
[10921160] |[[Rail transport in the United States#History|New railways]] made relocation much less arduous for settlers and increased conflicts with Native Americans.
[10921170] |Over a half-century, up to 40 million [[American Bison|American bison]], commonly called buffalo, were slaughtered for skins and meat and to ease the railways' spread.
[10921180] |The loss of the bison, a primary economic resource for the [[plains Indians]], was an existential blow to many native cultures.
[10921190] |===Civil War and industrialization=== 
[10921200] |[[Origins of the American Civil War|Tensions]] between slave and [[Free state (United States)|free states]] mounted with increasing disagreements over the relationship between the [[states' rights|state and federal governments]] and [[Bleeding Kansas|violent conflicts]] over the expansion of slavery into new states. [[Abraham Lincoln]], candidate of the largely antislavery [[Republican Party (United States)|Republican Party]], was elected president in 1860.
[10921210] |Before he took office, seven slave states declared their [[secession]] from the United States, forming the [[Confederate States of America]].
[10921220] |The federal government maintained secession was illegal, and with the Confederate [[Battle of Fort Sumter|attack upon Fort Sumter]], the [[American Civil War]] began and four more slave states joined the Confederacy.
[10921230] |The [[Union (American Civil War)|Union]] [[Emancipation Proclamation|freed Confederate slaves]] as its [[Union Army|army]] advanced through the South.
[10921240] |Following the Union victory in 1865, three amendments to the U.S. Constitution [[Thirteenth Amendment to the United States Constitution|ensured freedom]] for the nearly four million African Americans who had been slaves, [[Fourteenth Amendment to the United States Constitution|made them citizens]], and [[Fifteenth Amendment to the United States Constitution|gave them voting rights]].
[10921250] |The war and its resolution led to a substantial increase in [[Federalism|federal power]].
[10921260] |After the war, the [[Abraham Lincoln assassination|assassination of President Lincoln]] [[Radical Republican (USA)|radicalized Republican]] [[Reconstruction era of the United States|Reconstruction]] policies aimed at reintegrating and rebuilding the Southern states while ensuring the rights of the newly freed slaves.
[10921270] |The resolution of the disputed [[United States presidential election, 1876|1876 presidential election]] by the [[Compromise of 1877]] ended Reconstruction; [[Jim Crow laws]] soon [[Disfranchisement after the Civil War|disenfranchised many African Americans]].
[10921280] |In the North, urbanization and an unprecedented [[Immigration to the United States#Immigration 1850 to 1930|influx of immigrants]] hastened the [[United States technological and industrial history#Technological systems and infrastructure|country's industrialization]].
[10921290] |The wave of immigration, which lasted until 1929, provided labor for U.S. businesses and transformed American culture.
[10921300] |High tariff protections, national infrastructure building, and new banking regulations encouraged industrial growth.
[10921310] |The 1867 [[Alaska purchase]] from Russia completed the country's mainland expansion.
[10921320] |The [[Wounded Knee Massacre|Wounded Knee massacre]] in 1890 was the last major armed conflict of the [[Indian Wars]].
[10921330] |In 1893, the [[Ancient Hawaii|indigenous monarchy]] of the Pacific [[Kingdom of Hawaii]] was overthrown in a coup led by American residents; the archipelago was annexed by the United States in 1898.
[10921340] |Victory in the [[Spanish-American War]] that same year demonstrated that the United States was a [[Great power|major world power]] and resulted in the annexation of Puerto Rico and the [[Philippines]].
[10921350] |The Philippines gained independence a half-century later; Puerto Rico remains a [[Commonwealth (United States insular area)|commonwealth]] of the United States.
[10921360] |===World War I, Great Depression, and World War II=== 
[10921370] |At the outbreak of [[World War I]] in 1914, the United States remained neutral.
[10921380] |Americans sympathized with the British and French, although many citizens, mostly Irish and German, opposed intervention.
[10921390] |In 1917, the United States joined the [[Allies of World War I|Allies]], turning the tide against the [[Central Powers]].
[10921400] |Reluctant to be involved in European affairs, the Senate did not ratify the [[Treaty of Versailles (1919)|Treaty of Versailles]], which established the [[League of Nations]].
[10921410] |The country pursued a policy of [[unilateralism]], verging on [[isolationism]].
[10921420] |In 1920, the [[women's rights]] movement won passage of a [[Nineteenth Amendment to the United States Constitution|constitutional amendment]] granting [[History of women's suffrage in the United States|women's suffrage]].
[10921430] |Partly because of the service of many in the war, Native Americans gained [[United States nationality law|U.S. citizenship]] in the [[Indian Citizenship Act of 1924]].
[10921440] |During [[Roaring Twenties|most of the 1920s]], the United States enjoyed a period of unbalanced prosperity as farm profits fell while industrial profits grew.
[10921450] |A rise in debt and an inflated [[stock market]] culminated in the [[Wall Street Crash of 1929|1929 crash]] that triggered the [[Great Depression in the United States|Great Depression]].
[10921460] |After his election as president in 1932, [[Franklin D. Roosevelt]] responded with the [[New Deal]], a range of policies increasing government intervention in the economy.
[10921470] |The [[Dust Bowl]] of the mid-1930s impoverished many farming communities and spurred a new wave of western migration.
[10921480] |The nation would not fully recover from the economic depression until the industrial mobilization spurred by its entrance into [[World War II]].
[10921490] |The United States, effectively neutral during the war's early stages after the [[Invasion of Poland (1939)|Nazi invasion of Poland]] in September 1939, began supplying [[materiel]] to the [[Allies of World War II|Allies]] in March 1941 through the [[Lend-Lease]] program.
[10921500] |On [[December 7]], [[1941]], the United States joined the Allies against the [[Axis powers]] after a surprise [[attack on Pearl Harbor]] by [[Japan]].
[10921510] |World War II cost far more money than any other war in American history, but it boosted the economy by providing capital investment and jobs, while bringing many women into the labor market.
[10921520] |Among the major combatants, the United States was the only nation to become richer—indeed, far richer—instead of poorer because of the war.
[10921530] |Allied conferences at [[United Nations Monetary and Financial Conference|Bretton Woods]] and [[Yalta Conference|Yalta]] outlined a new system of [[international organization]]s that placed the [[United States and the United Nations|United States]] and [[Soviet Union and the United Nations|Soviet Union]] at the center of world affairs.
[10921540] |As [[Victory in Europe Day|victory was achieved in Europe]], a 1945 [[United Nations Conference on International Organization|international conference]] held in [[San Francisco, California|San Francisco]] produced the [[United Nations Charter]], which became active after the war.
[10921550] |The United States, having [[Manhattan Project|developed the first nuclear weapons]], used them on the Japanese cities of [[atomic bombings of Hiroshima and Nagasaki|Hiroshima and Nagasaki]] in August.
[10921560] |[[surrender of Japan|Japan surrendered]] on [[September 2]], ending the war.
[10921570] |===Cold War and civil rights=== 
[10921580] |The United States and Soviet Union jockeyed for power after World War II during the Cold War, dominating the military affairs of Europe through [[NATO]] and the [[Warsaw Pact]].
[10921590] |The United States promoted [[liberal democracy]] and [[capitalism]], while the Soviet Union promoted [[communism]] and a centrally [[planned economy]].
[10921600] |Both the United States and the Soviet Union supported dictatorships, and both engaged in [[proxy war]]s.
[10921610] |United States troops fought [[People's Republic of China|Communist Chinese]] forces in the [[Korean War]] of 1950–53.
[10921620] |The [[House Un-American Activities Committee]] pursued a series of investigations into suspected leftist subversion, while Senator [[Joseph McCarthy]] became the figurehead of anticommunist sentiment.
[10921630] |The Soviet Union launched the first manned spacecraft in 1961, prompting U.S. efforts to raise proficiency in mathematics and science and President [[John F. Kennedy]]'s call for the country to be first to land "a man on the moon," achieved in 1969.
[10921640] |Kennedy also faced a [[Cuban Missile Crisis|tense nuclear showdown]] with Soviet forces in Cuba.
[10921650] |Meanwhile, America experienced sustained economic expansion.
[10921660] |A growing [[African-American Civil Rights Movement (1955–1968)|civil rights movement]] headed by prominent African Americans, such as [[Martin Luther King, Jr.]], fought segregation and discrimination, leading to the abolition of [[Jim Crow laws]].
[10921670] |Following [[John F. Kennedy assassination|Kennedy's assassination]] in 1963, the [[Civil Rights Act of 1964]] was passed under President [[Lyndon B. Johnson]].
[10921680] |Johnson and his successor, [[Richard Nixon]], expanded a proxy war in Southeast Asia into the unsuccessful [[Vietnam War]].
[10921690] |As a result of the [[Watergate scandal]], in 1974 Nixon became the first U.S. president to [[resignation|resign]], rather than be [[impeachment|impeached]] on charges including [[obstruction of justice]] and [[political power|abuse of power]]; he was [[United States presidential line of succession|succeeded]] by Vice President [[Gerald Ford]].
[10921700] |During the [[Jimmy Carter]] administration in the late 1970s, the U.S. economy experienced [[stagflation]].
[10921710] |The election of [[Ronald Reagan]] as president in 1980 marked a significant [[Conservatism in the United States#Nixon, Reagan, and Bush|rightward shift in American politics]], reflected in major changes in [[Reaganomics|taxation and spending priorities]].
[10921720] |In the late 1980s and 1990s, the [[History of the Soviet Union (1985–1991)|Soviet Union's power diminished]], leading to its collapse and effectively ending the Cold War.
[10921730] |===Contemporary era=== 
[10921740] |The leadership role taken by the United States and its allies in the United Nations–sanctioned [[Gulf War]], under President [[George H. W. Bush]], and later the [[Yugoslav wars]] helped to preserve its position as the world's last remaining superpower.
[10921750] |The longest economic expansion in modern U.S. history—from March 1991 to March 2001—encompassed the administrations of Presidents [[George H.W. Bush]], [[Bill Clinton]], and [[George W. Bush]].
[10921760] |In 1998, Clinton was [[Impeachment of Bill Clinton|impeached by the House]] on charges relating to a [[Paula Jones|civil lawsuit]] and a [[Lewinsky scandal|sexual scandal]], but he was acquitted by the Senate and remained in office.
[10921770] |The 1990s also saw a rise in [[Islamic Terrorism]] against Americans from [[al-Qaeda]] and other groups, including an [[1993 World Trade Center bombing|attack on the World Trade Center in 1993]], an [[Battle of Mogadishu (1993)|attack on U.S. forces in Somalia]], the 1996 [[Khobar Towers bombing]], the [[1998 United States embassy bombings]] in Tanzania and Kenya, the [[2000 millennium attack plots]], and the [[USS Cole bombing]] in Yemen in October 2000.
[10921780] |In [[Iraq]], the regime of [[Saddam Hussein]] proved a continuing problem for the UN and its neighbors, prompting a variety of [[Iraq sanctions|UN sanctions]], Anglo-American patrolling of [[Iraqi no-fly zones]], [[Bombing of Iraq (December 1998)|Operation Desert Fox]], and the [[Iraq Liberation Act]] of 1998 which called for the removal of the Hussein regime and its replacement by a democratic system.
[10921790] |The [[United States presidential election, 2000|presidential election of 2000]] was one of the closest in U.S. history and saw [[George W. Bush]] become President of the United States.
[10921800] |[[September 11, 2001 attacks|On September 11, 2001]], [[al-Qaeda]] terrorists struck the [[World Trade Center]] in New York City and [[The Pentagon]] near Washington, D.C., killing nearly three thousand people.
[10921810] |In the aftermath, President Bush urged support from the international community for what was dubbed the [[War on Terrorism]].
[10921820] |In late 2001, U.S. forces launched [[Operation Enduring Freedom]] removing the [[Taliban]] government and [[al-Qaeda]] training camps.
[10921830] |Taliban insurgents continue to fight a [[Guerrilla warfare|guerrilla war]] against a NATO-led force.
[10921840] |Controversies arose regarding the conduct of the [[War on Terror]].
[10921850] |Using language from the 1998 [[Iraq Liberation Act]] and the [[Clinton Administration]], in 2002 the Bush Administration began to [[Rationale for the Iraq War|press]] for [[regime change]] in Iraq.
[10921860] |With [[Iraq Resolution|broad bipartisan support in the U.S. Congress]], Bush formed an international [[Coalition of the Willing]] and in March 2003 ordered [[Operation Iraqi Freedom]], removing [[Saddam Hussein]] from power.
[10921870] |Although facing pressure to withdraw, the U.S.-led coalition maintains a [[Iraq War troop surge of 2007|presence in Iraq]] and continues to train and mentor a [[Iraqi security forces|new Iraqi military]] as well as lead [[Reconstruction of Iraq|economic and infrastructure development]].
[10921880] |In the upcoming [[United States presidential election, 2008|2008 presidential election]], the [[Republican Party (United States)|Republican Party]] candidate, four-term Senator [[John McCain]] of [[Arizona]] – a former U.S. [[prisoner of war]] who served in the [[Vietnam War]] – will face the [[Democratic Party (United States)|Democratic Party]] candidate, freshman Senator [[Barack Obama]] of [[Illinois]], the first African American to head a major political party's presidential ticket.
[10921890] |==Government and elections== 
[10921900] |The United States is the world's oldest surviving [[federation]].
[10921910] |It is a [[constitutional republic]], "in which [[majority rule]] is tempered by [[minority rights]] protected by [[Law of the United States|law]]."
[10921920] |It is fundamentally structured as a [[representative democracy]], though U.S. citizens residing in the territories are excluded from voting for federal officials.
[10921930] |The government is regulated by a system of [[separation of powers|checks and balances]] defined by the United States Constitution, which serves as the country's supreme legal document and as a [[social contract]] for the people of the United States.
[10921940] |In the [[Federalism#United States|American federalist system]], citizens are usually subject to [[Political divisions of the United States|three levels of government]], federal, state, and local; the [[Local government in the United States|local government's]] duties are commonly split between [[County (United States)|county]] and municipal governments.
[10921950] |In almost all cases, executive and legislative officials are elected by a [[plurality voting system|plurality vote]] of citizens by district.
[10921960] |There is no [[proportional representation]] at the federal level, and it is very rare at lower levels.
[10921970] |Federal and state judicial and [[cabinet]] officials are typically nominated by the executive branch and approved by the legislature, although some state judges and officials are elected by popular vote.
[10921980] |The federal government is composed of three branches: 
[10921990] |* [[legislature|Legislative]]: The [[bicameralism|bicameral]] [[United States Congress|Congress]], made up of the [[United States Senate|Senate]] and the [[United States House of Representatives|House of Representatives]], makes [[federal law]], [[declaration of war|declares war]], approves treaties, has the [[power of the purse]], and has the power of [[impeachment]], by which it can remove sitting members of the government.
[10922000] |* [[Executive (government)|Executive]]: The [[President of the United States|president]] is the [[commander-in-chief]] of the military, can veto [[Bill (proposed law)|legislative bills]] before they become law, and appoints the [[United States Cabinet|Cabinet]] and other officers, who administer and enforce federal laws and policies.
[10922010] |* [[Judiciary|Judicial]]: The [[Supreme Court of the United States|Supreme Court]] and lower [[United States federal courts|federal courts]], whose judges are appointed by the president with Senate approval, interpret laws and can overturn laws they deem [[constitutionality|unconstitutional]].
[10922020] |The House of Representatives has 435 members, each representing a [[congressional district]] for a two-year term.
[10922030] |House seats are [[United States congressional apportionment|apportioned]] among the fifty states by population every tenth year.
[10922040] |As of the [[United States Census, 2000|2000 census]], seven states have the minimum of one representative, while California, the most populous state, has fifty-three.
[10922050] |Each state has two senators, elected [[at-large]] to six-year terms; one third of Senate seats are up for election every second year.
[10922060] |The president serves a four-year term and may be elected to the office [[Term limits in the United States|no more than twice]].
[10922070] |The president is [[United States presidential election|not elected by direct vote]], but by an indirect [[United States Electoral College|electoral college]] system in which the determining votes are apportioned by state.
[10922080] |The Supreme Court, led by the [[Chief Justice of the United States]], has nine members, who serve for life.
[10922090] |All laws and procedures of both state and federal governments are subject to review, and any law ruled in violation of the Constitution by the judicial branch is overturned.
[10922100] |The original text of the Constitution establishes the structure and responsibilities of the federal government, the relationship between it and the individual states, and essential matters of military and economic authority.
[10922110] |[[Article One of the United States Constitution|Article One]] protects the right to the "great writ" of [[Habeas corpus in the United States|habeas corpus]], and [[Article Three of the United States Constitution|Article Three]] guarantees the [[Jury trial#The United States|right to a jury trial]] in all criminal cases.
[10922120] |[[Article Five of the United States Constitution|Amendments to the Constitution]] require the approval of three-fourths of the states. The Constitution has been amended twenty-seven times; the first ten amendments, which make up the [[United States Bill of Rights|Bill of Rights]], and the [[Fourteenth Amendment to the United States Constitution|Fourteenth Amendment]] form the central basis of individual rights in the United States.
[10922130] |===Parties and politics=== 
[10922140] |Politics in the United States have operated under a [[two-party system]] for virtually all of the country's history.
[10922150] |For elective offices at all levels, state-administered [[primary election]]s are held to choose the major party nominees for subsequent [[general election]]s.
[10922160] |Since the [[United States presidential election, 1856|general election of 1856]], the two dominant parties have been the [[Democratic Party (United States)|Democratic Party]], [[History of the United States Democratic Party|founded in 1824]] (though its [[Democratic-Republican Party|roots trace back to 1792]]), and the [[Republican Party (United States)|Republican Party]], [[History of the United States Republican Party|founded in 1854]].
[10922170] |Since the Civil War, only one [[Third party (United States)|third-party]] presidential candidate—former president [[Theodore Roosevelt]], running as a [[Progressive Party (United States, 1912)|Progressive]] in [[United States presidential election, 1912|1912]]—has won as much as 20% of the popular vote.
[10922180] |The incumbent president, Republican [[George W. Bush]], is the [[List of Presidents of the United States|43rd president in the country's history]].
[10922190] |All U.S. presidents to date have been white men.
[10922200] |If Democrat [[Barack Obama]] wins the [[United States presidential election, 2008|forthcoming presidential election]], he will become the first African-American president.
[10922210] |Following the [[United States general elections, 2006|2006 midterm elections]], the Democratic Party controls both the House and the Senate.
[10922220] |Every member of the U.S. Congress is a Democrat or a Republican except two [[Independent (politician)|independent]] members of the Senate—one a former Democratic incumbent, the other a self-described [[socialism|socialist]].
[10922230] |An [[Political party strength in U.S. states|overwhelming majority]] of state and local officials are also either Democrats or Republicans.
[10922240] |Within American [[political culture]], the Republican Party is considered "center-right" or [[Conservatism in the United States|conservative]] and the Democratic Party is considered "center-left" or [[Modern liberalism in the United States|liberal]], but members of both parties have a wide range of views.
[10922250] |In a May 2008 poll, 44% of Americans described themselves as "conservative," 27% as "moderate," and 21% as "liberal."
[10922260] |On the other hand, that same month a plurality of adults, 41.7%, identified as Democrats, 31.6% as Republicans, and 26.6% as independents.
[10922270] |The states of the [[Northeastern United States#Politics|Northeast]] and [[Western United States#Politics|West Coast]] and some of the [[Great Lakes]] states are relatively liberal-leaning&mdash;they are known in political parlance as "[[Red states and blue states|blue states]]."
[10922280] |The "[[red states]]" of the [[Politics of the Southern United States|South]] and the [[Western United States#Politics|Rocky Mountains]] lean conservative.
[10922290] |==States== 
[10922300] |The United States is a [[federation|federal union]] of fifty states.
[10922310] |The original thirteen states were the successors of the [[Thirteen Colonies|thirteen colonies]] that rebelled against [[Great Britain|British]] rule.
[10922320] |Most of the rest have been carved from territory obtained through war or purchase by the U.S. government.
[10922330] |The exceptions are [[Vermont]], [[Texas]], and [[Hawaii]]; each was an independent republic before joining the union.
[10922340] |Early in the country's history, three states were created out of the territory of existing ones: [[Kentucky]] from [[Virginia]]; [[Tennessee]] from [[North Carolina]]; and [[Maine]] from [[Massachusetts]].
[10922350] |[[West Virginia]] broke away from Virginia during the [[American Civil War]].
[10922360] |The most recent state—Hawaii—achieved statehood on [[August 21]], [[1959]].
[10922370] |The [[Supreme Court of the United States|U.S. Supreme Court]] [[Texas v. White|has ruled]] that the states do not have the right to [[secession|secede]] from the union.
[10922380] |The states compose the vast bulk of the U.S. land mass; the only other areas considered integral parts of the country are the District of Columbia, the [[Capital districts and territories|federal district]] where the capital, Washington, is located; and [[Palmyra Atoll]], an uninhabited but [[territories of the United States|incorporated territory]] in the Pacific Ocean.
[10922390] |The United States possesses five major territories with indigenous populations: [[Puerto Rico]] and the [[United States Virgin Islands]] in the Caribbean; and [[American Samoa]], [[Guam]], and the [[Northern Mariana Islands]] in the Pacific.
[10922400] |Those born in the territories (except for American Samoa) possess [[Birthright citizenship in the United States of America|U.S. citizenship]].
[10922410] |==Foreign relations and military== 
[10922420] |The United States has vast economic, political, and military influence on a global scale, which makes its foreign policy a subject of great interest around the world.
[10922430] |Almost all countries have [[List of diplomatic missions in the United States|embassies]] in Washington, D.C., and many host [[Consul (representative)|consulates]] around the country.
[10922440] |Likewise, nearly all nations host [[Diplomatic missions of the United States|American diplomatic missions]].
[10922450] |However, [[Cuba-United States relations|Cuba]], [[United States-Iran relations|Iran]], [[North Korea-United States relations|North Korea]], [[Bhutan]], [[Sudan]], and the [[Republic of China]] (Taiwan) do not have formal diplomatic relations with the United States.
[10922460] |American [[isolationism|isolationists]] have often been at odds with internationalists, as anti-imperialists have been with promoters of [[Manifest Destiny]] and [[American Empire]].
[10922470] |American [[Philippine-American War|imperialism in the Philippines]] drew sharp rebukes from [[Mark Twain]], philosopher [[William James]], and many others.
[10922480] |Later, President [[Woodrow Wilson]] played a key role in creating the [[League of Nations]], but the Senate prohibited American membership in it.
[10922490] |Isolationism became a thing of the past when the United States took a lead role in founding the United Nations, becoming a permanent member of the [[United Nations Security Council|Security Council]] and host to the [[United Nations Headquarters]].
[10922500] |The United States enjoys a [[Special Relationship (US-UK)|special relationship]] with the [[Anglo-American relations|United Kingdom]] and strong ties with [[United States-Australia relations|Australia]], [[New Zealand-United States relations|New Zealand]], [[Japan-United States relations|Japan]], [[Israel-United States relations|Israel]], and fellow NATO members.
[10922510] |It also works closely with its neighbors through the [[Organization of American States]] and [[United States free trade agreements|free trade agreements]] such as the trilateral [[North American Free Trade Agreement]] with [[Canada – United States relations|Canada]] and [[United States-Mexico relations|Mexico]].
[10922520] |In 2005, the United States spent $27.3 billion on [[official development assistance]], the most in the world; however, as a share of [[Gross National Income|gross national income]] (GNI), the U.S. contribution of 0.22% ranked twentieth of twenty-two donor states.
[10922530] |On the other hand, nongovernmental sources such as private foundations, corporations, and educational and religious institutions donated $95.5 billion.
[10922540] |The total of $122.8 billion is again the most in the world and seventh in terms of GNI percentage.
[10922550] |The president holds the title of commander-in-chief of the nation's armed forces and appoints its leaders, the [[United States Secretary of Defense|secretary of defense]] and the [[Joint Chiefs of Staff]].
[10922560] |The [[United States Department of Defense]] administers the armed forces, including the [[United States Army|Army]], the [[United States Navy|Navy]], the [[United States Marine Corps|Marine Corps]], and the [[United States Air Force|Air Force]].
[10922570] |The [[United States Coast Guard|Coast Guard]] falls under the jurisdiction of the [[United States Department of Homeland Security|Department of Homeland Security]] in peacetime and the [[United States Department of the Navy|Department of the Navy]] in times of war.
[10922580] |In 2005, the military had 1.38 million personnel on active duty, along with several hundred thousand each in the [[Reserve component of the Armed Forces of the United States|Reserves]] and the [[National Guard of the United States|National Guard]] for a total of [[List of countries by number of total troops|2.3 million troops]].
[10922590] |The Department of Defense also employs approximately 700,000 civilians, disregarding contractors.
[10922600] |Military service is voluntary, though [[Conscription in the United States|conscription]] may occur in wartime through the [[Selective Service System]].
[10922610] |The rapid deployment of American forces is facilitated by the Air Force's large fleet of transportation aircraft and aerial refueling tankers, the Navy's fleet of eleven active aircraft carriers, and [[Marine Expeditionary Unit]]s at sea in the Navy's [[United States Fleet Forces Command|Atlantic and]] [[Commander United States Pacific Fleet|Pacific fleets]].
[10922620] |Outside of the American homeland, the U.S. military is [[Deployments of the United States Military|deployed to 770 bases and facilities]], on every continent [[Military activity in the Antarctic|except Antarctica]].
[10922630] |Because of the extent of its global military presence, scholars describe the United States as maintaining an "empire of bases."
[10922640] |Total U.S. military spending in 2006, over $528 billion, was 46% of the entire military spending in the world and greater than the next fourteen largest national military expenditures combined.
[10922650] |(In [[purchasing power parity]] terms, it was larger than the next six such expenditures combined.)
[10922660] |The per capita spending of $1,756 was approximately ten times the world average.
[10922670] |At 4.06% of GDP, U.S. military spending is ranked 27th out of 172 nations.
[10922680] |The proposed base [[military budget of the United States|Department of Defense budget]] for 2009, $515.4 billion, is a 7% increase over 2008 and a nearly 74% increase over 2001.
[10922690] |The estimated total cost of the [[Iraq War]] to the United States through 2016 is $2.267 trillion.
[10922700] |As of [[June 6]], [[2008]], the United States had suffered 4,092 military fatalities during the war and nearly 30,000 wounded.
[10922710] |==Economy== 
[10922720] |The United States has a [[capitalism|capitalist]] [[mixed economy]], which is fueled by abundant [[natural resource]]s, a well-developed infrastructure, and high productivity.
[10922730] |According to the [[International Monetary Fund]], the United States GDP of more than $13 trillion constitutes over 25.5% of the [[gross world product]] at market exchange rates and over 19% of the gross world product at [[purchasing power parity]] (PPP).
[10922740] |The largest national GDP in the world, it was slightly less than the combined GDP of the [[European Union]] at PPP in 2006.
[10922750] |The country ranks eighth in the world in [[List of countries by GDP (nominal) per capita|nominal GDP per capita]] and fourth in [[List of countries by GDP (PPP) per capita|GDP per capita at PPP]].
[10922760] |The United States is the largest importer of goods and third largest exporter, though [[List of countries by exports per capita|exports per capita]] are relatively low.
[10922770] |Canada, China, Mexico, Japan, and Germany are its top trading partners.
[10922780] |The leading export commodity is electrical machinery, while vehicles constitute the leading import.
[10922790] |The private sector constitutes the bulk of the economy, with government activity accounting for 12.4% of GDP.
[10922800] |The economy is [[post-industrial society|postindustrial]], with the [[Tertiary sector of economic activity|service sector]] contributing 67.8% of GDP.
[10922810] |The leading business field by gross business receipts is wholesale and retail trade; by net income it is finance and insurance.
[10922820] |The United States remains an industrial power, with chemical products the leading manufacturing field.
[10922830] |The United States is the third largest producer of oil in the world.
[10922840] |It is the world's number one producer of electrical and nuclear energy, as well as liquid natural gas, sulfur, phosphates, and salt.
[10922850] |While [[Agriculture in the United States|agriculture]] accounts for just under 1% of GDP, the United States is the world's top producer of corn and soybeans.
[10922860] |The country's leading cash crop is [[Legal history of marijuana in the United States|marijuana]], despite federal laws making its [[Legality of cannabis#United States|cultivation and sale illegal]].
[10922870] |The [[New York Stock Exchange]] is the world's largest by dollar volume.
[10922880] |[[Coca-Cola]] and [[McDonald's]] are the two most recognized brands in the world.
[10922890] |In 2005, 155 million persons were employed with earnings, of whom 80% worked in full-time jobs.
[10922900] |The majority, 79%, were employed in the service sector.
[10922910] |With approximately 15.5 million people, health care and social assistance is the leading field of employment.
[10922920] |About 12% of American workers are [[Labor unions in the United States|unionized]], compared to 30% in Western Europe.
[10922930] |The U.S. ranks number one in the ease of hiring and firing workers, according to the World Bank.
[10922940] |Between 1973 and 2003, a year's work for the average American grew by 199 hours.
[10922950] |Partly as a result, the United States maintains the highest labor productivity in the world.
[10922960] |However, it no longer leads the world in productivity per hour as it did from the 1950s through the early 1990s; workers in [[Norway]], France, [[Belgium]], and [[Luxembourg]] are now more productive per hour.
[10922970] |The United States ranks third in the [[World Bank Group|World Bank's]] [[Ease of Doing Business Index]].
[10922980] |Compared to Europe, U.S. property and corporate [[Taxation in the United States|income taxes]] are generally higher, while labor and, particularly, consumption taxes are lower.
[10922990] |===Income and human development=== 
[10923000] |According to the [[United States Census Bureau|Census Bureau]], the pretax [[median household income]] in 2006 was $48,201.
[10923010] |The two-year average ranged from $66,752 in [[New Jersey]] to $34,343 in [[Mississippi]].
[10923020] |Using [[purchasing power parity]] exchange rates, the overall median is similar to the most affluent cluster of [[Household income in the United States#International comparison|developed nations]].
[10923030] |After having declined sharply throughout the mid 20<sup>th</sup> century, [[Poverty in the United States|poverty rates]] have plateaued since the early 1970s, with roughly 12.3% or 13.3% of Americans below the federally designated [[poverty threshold|poverty line]] in any given year.
[10923040] |Owing to lackluster expansion since the late 1970s, the U.S. welfare state is now among the most austere in the developed world, reducing [[relative poverty]] by roughly 30% and [[absolute poverty]] by roughly 40%; considerably less than the mean for rich nations.
[10923050] |While the American welfare state preforms well in reducing poverty among the elderly, from an estimated 50% to 10%, it lacks extensive programs geared towards the well-being of the young.
[10923060] |A 2007 [[United Nations Children's Fund|UNICEF]] study of children's well-being in twenty-one industrialized nations, covering a broad range of factors, ranked the U.S. next to last.
[10923070] |Between 1947 and 1979, [[Real income|real median income]] rose by over 80% for all classes, more so for the poor than the rich.
[10923080] |While [[median household income]] has increased for all classes since 1980, largely owing to more dual earner households, the closing of the gender gap and longer work hours, growth has been slower and strongly titled towards the very top (see graph).
[10923090] |As a result the share of income of the top 1% has doubbled since 1979, leaving the U.S. with the highest level of income inequality among developed nations.
[10923100] |While some economists do not see inequality as a considerable problem, most see it as a problem requiring government action.
[10923110] |Wealth is highly concentrated: The richest 10% of the adult population possesses 69.8% of the country's household wealth, the second-highest share of any democratic developed nation.
[10923120] |The top 1% possesses 33.4% of net wealth.
[10923130] |===Science and technology=== 
[10923140] |The United States has been a leader in scientific research and technological innovation since the late nineteenth century.
[10923150] |In 1876, [[Alexander Graham Bell]] was awarded the first U.S. [[Invention of the telephone|patent for the telephone]].
[10923160] |The [[Edison, New Jersey|laboratory]] of [[Thomas Edison]] developed the [[Phonograph#The first phonograph|phonograph]], the first [[Incandescent light bulb#History of the light bulb|long-lasting light bulb]], and the first viable [[Kinetoscope|movie camera]].
[10923170] |In the early twentieth century, the automobile companies of [[Ransom E. Olds]] and [[Henry Ford]] pioneered [[assembly line]] manufacturing.
[10923180] |The [[Wright brothers]], in 1903, made what is recognized as the "[[first flying machine|first sustained and controlled heavier-than-air powered flight]]."
[10923190] |The rise of [[Nazism]] in the 1930s led many important European scientists, including [[Albert Einstein]] and [[Enrico Fermi]], to immigrate to the United States.
[10923200] |During World War II, the U.S.-based [[Manhattan Project]] developed nuclear weapons, ushering in the [[Atomic Age]].
[10923210] |The [[Space Race]] produced rapid advances in rocketry, [[materials science]], and computers.
[10923220] |The United States largely developed the [[ARPANET]] and its successor, the [[Internet]].
[10923230] |Today, the bulk of [[research and development]] funding, 64%, comes from the private sector.
[10923240] |The United States leads the world in scientific research papers and [[impact factor]].
[10923250] |Americans enjoy high levels of access to technological consumer goods, and almost half of U.S. households have [[Broadband Internet access|broadband Internet service]].
[10923260] |The country is the primary developer and grower of [[genetically modified food]]; more than half of the world's land planted with biotech crops is in the United States.
[10923270] |===Transportation=== 
[10923280] |As of 2003, there were 759 automobiles per 1,000 Americans, compared to 472 per 1,000 inhabitants of the European Union the following year.
[10923290] |Approximately 39% of [[Passenger vehicles in the United States|personal vehicles]] are vans, [[Sport utility vehicle|SUVs]], or light trucks.
[10923300] |The average American adult (accounting for all drivers and nondrivers) spends 55 minutes behind the wheel every day, driving .
[10923310] |The U.S. intercity passenger rail system is relatively weak.
[10923320] |Only 9% of total U.S. work trips employ [[public transport|mass transit]], compared to 38.8% in Europe.
[10923330] |Bicycle usage is minimal, well below European levels.
[10923340] |The civil airline industry is entirely privatized, while most major airports are publicly owned.
[10923350] |The five largest airlines in the world by passengers carried are all American; [[American Airlines]] is number one.
[10923360] |Of the world's thirty busiest passenger airports, sixteen are in the United States, including the busiest, [[Hartsfield-Jackson Atlanta International Airport]] (ATL).
[10923370] |===Energy=== 
[10923380] |The United States energy market is 29,000 [[terawatt]] hours per year.
[10923390] |[[List of countries by energy consumption per capita|Energy consumption per capita]] is 7.8 tons of oil equivalent per year, compared to Germany's 4.2 tons and Canada's 8.3 tons.
[10923400] |In 2005, 40% of the nation's energy came from petroleum, 23% from coal, and 22% from natural gas.
[10923410] |The remainder was supplied by nuclear power and various [[renewable energy]] sources.
[10923420] |The United States is the world's largest consumer of petroleum.
[10923430] |For decades, nuclear power has played a limited role relative to many other developed countries.
[10923440] |Recently, applications for new nuclear plants have been filed.
[10923450] |==Demographics== 
[10923460] |As of 2008, the United States population was estimated by the U.S. Census Bureau to be 304,516,000.
[10923470] |The U.S. population included an estimated 12 million [[Illegal immigration to the United States|unauthorized migrants]], of whom an estimated 1 million were uncounted by the Census Bureau.
[10923480] |The overall [[Population growth|growth rate]] is 0.89%, compared to 0.16% in the European Union.
[10923490] |The [[birth rate]] of 14.16 per 1,000 is 30% below the world average, while higher than any European country except for [[Albania]] and [[Republic of Ireland|Ireland]].
[10923500] |In 2006, 1.27 million immigrants were granted [[United States Permanent Resident Card|legal residence]].
[10923510] |Mexico has been the leading source of new U.S. residents for over two decades; since 1998, China, India, and the Philippines have been in the top four sending countries every year.
[10923520] |The United States is the only industrialized nation in which large population increases are projected.
[10923530] |The United States has a very [[multiethnic society|diverse population]]—thirty-one [[maps of American ancestries|ancestry groups]] have more than a million members.
[10923540] |[[White American|Whites]] are the largest [[racial group]], with [[German American]]s, [[Irish American]]s, and [[English American]]s constituting three of the country's four largest ancestry groups.
[10923550] |[[African American]]s constitute the nation's largest [[Minority group|racial minority]] and third largest ancestry group.
[10923560] |[[Asian American]]s are the country's second largest racial minority; the two largest Asian American ancestry groups are [[Chinese American|Chinese]] and [[Filipino American|Filipino]].
[10923570] |In 2006, the U.S. population included an estimated 4.5 million people with some [[Native Americans in the United States|American Indian]] or [[Alaska Native|Alaskan native]] ancestry (2.9 million exclusively of such ancestry) and over 1 million with some [[Native Hawaiians|native Hawaiian]] or [[Pacific Islander|Pacific island]] ancestry (0.5 million exclusively).
[10923580] |The population growth of [[Hispanic and Latino Americans]] has been a major [[Demographic transition|demographic trend]].
[10923590] |Approximately 44 million Americans are of Hispanic descent, with about 64% possessing [[Mexican]] ancestry.
[10923600] |Between 2000 and 2006, the country's Hispanic population increased 25.5% while the non-Hispanic population rose just 3.5%.
[10923610] |Much of this growth is from immigration; as of 2004, 12% of the U.S. population was foreign-born, over half that number from [[Latin America]].
[10923620] |Fertility is also a factor; the average Hispanic woman gives birth to three children in her lifetime.
[10923630] |The comparable fertility rate is 2.2 for non-Hispanic black women and 1.8 for non-Hispanic white women (below the [[Total fertility rate#Replacement rates|replacement rate]] of 2.1).
[10923640] |Hispanics and Latinos accounted for nearly half of the national population growth of 2.9 million between July 2005 and July 2006.
[10923650] |About 83% of the population lives in one of the country's 363 [[Table of United States Metropolitan Statistical Areas|metropolitan areas]].
[10923660] |In 2006, 254 [[incorporated place]]s in the United States had populations over 100,000, nine cities had more than 1 million residents, and four [[global city|global cities]] had over 2 million ([[New York City]], [[Los Angeles, California|Los Angeles]], [[Chicago]], and [[Houston, Texas|Houston]]).
[10923670] |The United States has fifty [[Table of United States Metropolitan Statistical Areas|metropolitan areas]] with populations greater than 1 million.
[10923680] |Of the fifty fastest-growing metro areas, twenty-three are in the West and twenty-five in the South.
[10923690] |Among the country's twenty most populous metro areas, those of [[Dallas, Texas|Dallas]] (the fourth largest), Houston (sixth), and [[Atlanta, Georgia|Atlanta]] (ninth) saw the largest numerical gains between 2000 and 2006, while that of [[Phoenix, Arizona|Phoenix]] (thirteenth) grew the largest in percentage terms.
[10923700] |===Language=== 
[10923710] |[[American English|English]] is the de facto [[national language]].
[10923720] |Although there is no [[official language]] at the federal level, some laws—such as [[United_States_nationality_law#Naturalization|U.S. naturalization requirements]]—standardize English.
[10923730] |In 2003, about 215 million, or 82% of the population aged five years and older, spoke only English at home.
[10923740] |[[Spanish language|Spanish]], spoken by over 10% of the population at home, is the second most common language and the most widely taught [[foreign language]].
[10923750] |Some Americans advocate making English the country's official language, as it is in at least twenty-eight states.
[10923760] |Both [[Hawaiian language|Hawaiian]] and English are official languages in Hawaii by state law.
[10923770] |While neither has an official language, [[New Mexico]] has laws providing for the use of both English and Spanish, as [[Louisiana]] does for English and [[French language|French]].
[10923780] |Other states, such as [[California]], mandate the publication of Spanish versions of certain government documents including court forms.
[10923790] |Several insular territories grant official recognition to their native languages, along with English: [[Samoan language|Samoan]] and [[Chamorro language|Chamorro]] are recognized by Samoa and Guam, respectively; [[Carolinian language|Carolinian]] and Chamorro are recognized by the Northern Mariana Islands; Spanish is an official language of Puerto Rico.
[10923800] |===Religion=== 
[10923810] |The United States government does not audit Americans' religious beliefs.
[10923820] |In a private survey conducted in 2001, 76.5% of American adults identified themselves as [[Christianity in the United States|Christian]], down from 86.4% in 1990.
[10923830] |[[Protestantism|Protestant]] denominations accounted for 52% of adult Americans, while [[Roman Catholicism in the United States|Roman Catholics]], at 24.5%, were the largest individual denomination.
[10923840] |A different study describes white [[evangelicalism|evangelicals]], 26.3% of the population, as the country's largest religious cohort; evangelicals of all races are estimated at 30–35%.
[10923850] |The total reporting non-Christian religions in 2001 was 3.7%, up from 3.3% in 1990.
[10923860] |The leading non-Christian faiths were [[American Jews|Judaism]] (1.4%), [[Islam in the United States|Islam]] (0.5%), [[Buddhism in the United States|Buddhism]] (0.5%), [[Hinduism in the United States|Hinduism]] (0.4%), and [[Unitarian Universalism]] (0.3%).
[10923870] |Between 1990 and 2001, the number of Muslims and Buddhists more than doubled.
[10923880] |From 8.2% in 1990, 14.1% in 2001 described themselves as [[agnosticism|agnostic]], [[atheism|atheist]], or simply having [[irreligion|no religion]], still significantly less than in other postindustrial countries such as Britain (2005:44%) and [[Sweden]] (2001:69%, 2005:85%).
[10923890] |===Education=== 
[10923900] |American [[public education]] is operated by state and local governments, regulated by the [[United States Department of Education]] through restrictions on federal grants.
[10923910] |Children are required in most states to attend school from the age of six or seven (generally, [[kindergarten]] or [[first grade]]) until they turn eighteen (generally bringing them through [[Twelfth grade|12th grade]], the end of [[high school]]); some states allow students to leave school at sixteen or seventeen.
[10923920] |About 12% of children are enrolled in [[parochial school|parochial]] or [[nonsectarian]] [[private school]]s.
[10923930] |Just over 2% of children are [[homeschooling|homeschooled]].
[10923940] |The United States has many competitive private and public [[List of American institutions of higher education|institutions of higher education]], as well as local [[community college]]s of varying quality with open admission policies.
[10923950] |Of Americans twenty-five and older, 84.6% graduated from high school, 52.6% attended some college, 27.2% earned a [[bachelor's degree]], and 9.6% earned graduate degrees.
[10923960] |The basic [[literacy#United States|literacy rate]] is approximately 99%.
[10923970] |The United Nations assigns the United States an Education Index of 0.97, tying it for twelfth-best in the world.
[10923980] |===Health=== 
[10923990] |The American [[life expectancy]] of 77.8 years at birth is a year shorter than the overall figure in Western Europe, and three to four years lower than that of [[Norway]], [[Switzerland]], and [[Canada]].
[10924000] |Over the past two decades, the country's rank in life expectancy has dropped from 11th to 42nd place in the world.
[10924010] |The [[infant mortality|infant mortality rate]] of 6.37 per thousand likewise places the United States 42nd out of 221 countries, behind all of Western Europe.
[10924020] |U.S. cancer survival rates are the highest in the world.
[10924030] |Approximately one-third of the adult population is [[obesity|obese]] and an additional third is overweight; the obesity rate, the highest in the industrialized world, has more than doubled in the last quarter-century.
[10924040] |Obesity-related [[diabetes mellitus type 2|type 2 diabetes]] is considered [[epidemic]] by healthcare professionals.
[10924050] |The U.S. adolescent pregnancy rate, 79.8 per 1,000 women, is nearly four times that of France and five times that of Germany.
[10924060] |[[Abortion in the United States]], legal on demand, is a source of great political controversy.
[10924070] |Many states ban public funding of the procedure and have laws to restrict late-term abortions, require parental notification for minors, and mandate a waiting period prior to treatment.
[10924080] |While the incidence of abortion is in decline, the U.S. abortion ratio of 241 per 1,000 live births and abortion rate of 15 per 1,000 women aged 15–44 remain higher than those of most Western nations.
[10924090] |The United States healthcare system far outspends any other nation's, measured in both per capita spending and percentage of GDP.
[10924100] |Unlike most developed countries, the U.S. healthcare system is not [[Universal health care|universal]], and relies on a higher proportion of private funding.
[10924110] |In 2004, private insurance paid for 36% of personal health expenditure, private out-of-pocket payments covered 15%, and federal, state, and local governments paid for 44%.
[10924120] |The [[World Health Organization]] ranked the U.S. healthcare system in 2000 as first in responsiveness, but 37th in overall performance.
[10924130] |The United States is a leader in medical innovation.
[10924140] |In 2004, the U.S. nonindustrial sector spent three times as much as Europe per capita on biomedical research.
[10924150] |Medical bills are the most common reason for personal [[bankruptcy]] in the United States.
[10924160] |In 2005, 46.6 million Americans, or 15.9% of the population, were uninsured, 5.4 million more than in 2001.
[10924170] |The primary cause of the decline in coverage is the drop in the number of Americans with employer-sponsored health insurance, which fell from 62.6% in 2001 to 59.5% in 2005.
[10924180] |Approximately one third of the uninsured lived in households with annual incomes greater than $50,000, with half of those having an income over $75,000.
[10924190] |Another third were eligible but not registered for public health insurance.
[10924200] |In 2006, Massachusetts became the first state to mandate health insurance; California is considering similar legislation.
[10924210] |===Crime and punishment=== 
[10924220] |Law enforcement in the United States is primarily the responsibility of local police and [[sheriff]]'s departments, with [[state police]] providing broader services.
[10924230] |Federal agencies such as the [[Federal Bureau of Investigation]] (FBI) and the [[United States Marshals Service|U.S. Marshals Service]] have specialized duties.
[10924240] |At the federal level and in almost every state, jurisprudence operates on a [[common law]] system.
[10924250] |State courts conduct most criminal trials; [[United States federal courts|federal courts]] handle certain designated crimes as well as [[appeal]]s from state systems.
[10924260] |Among [[developed country|developed nations]], the United States has above-average levels of violent crime and particularly high levels of [[Gun violence in the United States|gun violence]] and homicide.
[10924270] |In 2006, there were 5.7 murders per 100,000 persons, three times the rate in neighboring Canada.
[10924280] |The U.S. homicide rate, which decreased by 42% between 1991 and 1999, has been roughly steady since.
[10924290] |Some scholars have associated the high rate of homicide with the country's high rates of [[Gun politics in the United States|gun ownership]], in turn associated with [[Gun law in the United States|U.S. gun laws]] which are very permissive compared to those of other developed countries.
[10924300] |The United States has the highest documented [[incarceration]] rate and total prison population in the world and by far the highest figures among democratic, developed nations.
[10924310] |At the start of 2008, more than 2.3 million people were held in American prisons or jails, more than one in every 100 adults.
[10924320] |The current rate is almost seven times the 1980 figure.
[10924330] |African American males are jailed at over six times the rate of white males and three times the rate of Hispanic males.
[10924340] |In the latest comparable data, from 2006, the U.S. incarceration rate was more than three times the figure in Poland, the [[Organisation for Economic Co-operation and Development]] (OECD) country with the next highest rate.
[10924350] |The country's extraordinary rate of incarceration is largely caused by changes in [[Federal Sentencing Guidelines|sentencing]] and [[Drug policy of the United States|drug]] policies.
[10924360] |Though it has been abolished in most Western nations, [[capital punishment]] is sanctioned in the United States for certain federal and military crimes, and in thirty-seven states.
[10924370] |Since 1976, when the U.S. Supreme Court [[Gregg v. Georgia|reinstated the death penalty]] after a four-year moratorium, there have been over 1,000 executions in the United States.
[10924380] |In 2006, the country had the sixth highest number of executions in the world, following China, Iran, Pakistan, Iraq, and Sudan.
[10924390] |In December 2007, New Jersey became the first state to abolish the death penalty since the 1976 Supreme Court decision.
[10924400] |==Culture== 
[10924410] |The United States is a [[multicultural]] nation, home to a wide variety of ethnic groups, traditions, and values.
[10924420] |There is no "American" ethnicity; aside from the now relatively small [[Native Americans in the United States|Native American]] population, nearly all Americans or their ancestors immigrated within the past five centuries.
[10924430] |The culture held in common by the majority of Americans is referred to as mainstream American culture, a [[Western culture]] largely derived from the traditions of [[Western Europe]]an migrants, beginning with the early [[culture of England|English]] and [[Dutch American|Dutch]] settlers.
[10924440] |[[German_American#German_American_influence|German]], [[Irish American|Irish]], and [[Scottish American|Scottish]] cultures have also been very influential.
[10924450] |Certain cultural attributes of [[Mandé peoples|Mandé]] and [[Wolof people|Wolof]] slaves from West Africa were adopted by the American mainstream; based more on the traditions of Central African [[Bantu peoples|Bantu]] slaves, a distinct [[African American culture]] developed that would eventually have a major effect on the mainstream as well.
[10924460] |Westward expansion integrated the [[Louisiana Creole people|Creoles]] and [[Cajun]]s of Louisiana and the [[Hispanos]] of the Southwest and brought close contact with the [[culture of Mexico]].
[10924470] |Large-scale immigration in the late nineteenth and early twentieth centuries from [[Southern Europe|Southern]] and [[Eastern Europe]] introduced many new cultural elements.
[10924480] |More recent immigration from [[Asian American|Asia]] and especially [[Latin American culture|Latin America]] has had broad impact.
[10924490] |The resulting mix of cultures may be characterized as a homogeneous [[melting pot]] or as a pluralistic [[Salad bowl (cultural idea)|salad bowl]] in which immigrants and their descendants retain distinctive cultural characteristics.
[10924500] |While American culture maintains that the United States is a [[classless society]], economists and sociologists have identified cultural differences between the country's social classes, affecting [[socialization]], language, and values.
[10924510] |The American [[American middle class|middle]] and [[American middle class#The professional/managerial middle class|professional class]] has been the source of many contemporary social trends such as [[feminism]], [[environmentalism]], and [[multiculturalism]].
[10924520] |Americans' self-images, social viewpoints, and cultural expectations are associated with their occupations to an unusually close degree.
[10924530] |While Americans tend greatly to value socioeconomic achievement, being [[Average Joe|ordinary or average]] is generally seen as a positive attribute.
[10924540] |Though the [[American Dream]], or the perception that Americans enjoy high [[social mobility]], played a key role in attracting immigrants, particularly in the late 1800s, some analysts find that the United States has less social mobility than Western Europe and Canada.
[10924550] |Women, many of whom were formerly more limited to domestic roles, now mostly work outside the home and receive a majority of [[Educational attainment in the United States|bachelor's degrees]].
[10924560] |The changing role of women has also changed [[Society of the United States#Household arrangements|the American family]].
[10924570] |In 2005, no household arrangement defined more than 30% of households; married childless couples were most common, at 28%.
[10924580] |The extension of marital rights to homosexual persons is an issue of debate; several more liberal states permit [[Civil union in the United States|civil union]]s in lieu of marriage.
[10924590] |In 2003, the [[Massachusetts Supreme Judicial Court]] [[Goodridge v. Department of Public Health|ruled]] that state's [[Same-sex marriage in Massachusetts|ban on same-sex marriage]] unconstitutional; the [[Supreme Court of California]] [[In re Marriage Cases|ruled]] [[Same-sex marriage in California|similarly]] in 2008.
[10924600] |Forty-three states still legally restrict marriage to the traditional man-and-woman model.
[10924610] |===Popular media=== 
[10924620] |In 1878, [[Eadweard Muybridge]] demonstrated the power of photography to capture motion.
[10924630] |In 1894, the world's first commercial motion picture exhibition was given in New York City, using [[Thomas Edison]]'s [[Kinetoscope]].
[10924640] |The next year saw the first commercial screening of a projected film, also in New York, and the United States was in the forefront of [[sound film]]'s development in the following decades.
[10924650] |Since the early twentieth century, the U.S. film industry has largely been based in and around [[Hollywood, Los Angeles, California|Hollywood, California]].
[10924660] |Director [[D. W. Griffith]] was central to the development of [[film grammar]] and [[Orson Welles]]'s ''[[Citizen Kane]]'' (1941) is frequently cited in critics' polls as the greatest film of all time.
[10924670] |American screen actors like [[John Wayne]] and [[Marilyn Monroe]] have become iconic figures, while producer/entrepreneur [[Walt Disney]] was a leader in both [[Animation|animated film]] and movie [[merchandising]].
[10924680] |The [[major film studio]]s of Hollywood are the primary source of the most commercially successful movies in the world, such as ''[[Star Wars Episode IV: A New Hope|Star Wars]]'' (1977) and ''[[Titanic (1997 film)|Titanic]]'' (1997), and the products of Hollywood today dominate the global film industry.
[10924690] |Americans are the heaviest television viewers in the world, and the average time spent in front of the screen continues to rise, hitting five hours a day in 2006.
[10924700] |The four major broadcast networks are all commercial entities.
[10924710] |Americans listen to radio programming, also largely commercialized, on average just over two-and-a-half hours a day.
[10924720] |Aside from [[web portal]]s and [[web search engine]]s, the most popular websites are [[eBay]], [[MySpace]], [[Amazon.com]], [[The New York Times]], and [[Apple Inc.|Apple]].
[10924730] |Twelve million Americans keep a blog.
[10924740] |The rhythmic and lyrical styles of [[African American music]] have deeply influenced [[Music of the United States|American music]] at large, distinguishing it from European traditions.
[10924750] |Elements from [[Folk music|folk]] idioms such as the [[blues]] and what is now known as [[old-time music]] were adopted and transformed into [[popular music|popular genres]] with global audiences.
[10924760] |[[Jazz]] was developed by innovators such as [[Louis Armstrong]] and [[Duke Ellington]] early in the twentieth century.
[10924770] |[[Country music]], [[rhythm and blues]], and [[rock and roll]] emerged between the 1920s and 1950s.
[10924780] |In the 1960s, [[Bob Dylan]] emerged from the [[American folk music revival|folk revival]] to become one of America's greatest songwriters and [[James Brown]] led the development of [[funk]].
[10924790] |More recent American creations include [[hip hop music|hip hop]] and [[house music]].
[10924800] |American pop stars such as [[Elvis Presley]], [[Michael Jackson]], and [[Madonna (entertainer)|Madonna]] have become global celebrities.
[10924810] |===Literature, philosophy, and the arts=== 
[10924820] |In the eighteenth and early nineteenth centuries, American art and literature took most of its cues from Europe.
[10924830] |Writers such as [[Nathaniel Hawthorne]], [[Edgar Allan Poe]], and [[Henry David Thoreau]] established a distinctive American literary voice by the middle of the nineteenth century.
[10924840] |[[Mark Twain]] and poet [[Walt Whitman]] were major figures in the century's second half; [[Emily Dickinson]], virtually unknown during her lifetime, is recognized as another essential American poet.
[10924850] |Eleven U.S. citizens have won the [[Nobel Prize in Literature]], most recently [[Toni Morrison]] in 1993.
[10924860] |[[Ernest Hemingway]], the 1954 Nobel laureate, is often named as one of the most influential writers of the twentieth century.
[10924870] |A work seen as capturing fundamental aspects of the national experience and character—such as [[Herman Melville]]'s ''[[Moby-Dick]]'' (1851), Twain's ''[[Adventures of Huckleberry Finn|The Adventures of Huckleberry Finn]]'' (1885), and [[F. Scott Fitzgerald]]'s ''[[The Great Gatsby]]'' (1925)—may be dubbed the "[[Great American Novel]]."
[10924880] |Popular literary genres such as the [[Western fiction|Western]] and [[Hardboiled|hardboiled crime fiction]] developed in the United States. [[postmodern literature|Postmodernism]] is the most recent major literary movement in the world, and though on the [[literary criticism|theory]] side postmodernism began with French writers like [[Jacques Derrida]] and [[Alain Robbe-Grillet]], and was transitioned into largely by Irish writer [[Samuel Beckett]], it has since been dominated by American writers such as [[Thomas Pynchon]], [[Don DeLillo]], [[William S. Burroughs]], [[Jack Kerouac]], [[John Barth]], [[E.L. Doctorow]], [[Kurt Vonnegut]] and many others.
[10924890] |The [[transcendentalism|transcendentalists]], led by [[Ralph Waldo Emerson]] and Thoreau, established the first major American [[philosophical movement]].
[10924900] |After the Civil War, [[Charles Peirce]] and then [[William James]] and [[John Dewey]] were leaders in the development of [[pragmatism]].
[10924910] |In the twentieth century, the work of [[Willard Van Orman Quine|W. V. Quine]] and [[Richard Rorty]] helped bring [[analytic philosophy]] to the fore in U.S. academic circles.
[10924920] |In the visual arts, the [[Hudson River School]] was an important mid-nineteenth-century movement in the tradition of European [[Naturalism (arts)|naturalism]].
[10924930] |The 1913 [[Armory Show]] in New York City, an exhibition of European [[Modern art|modernist art]], shocked the public and transformed the U.S. art scene.
[10924940] |[[Georgia O'Keeffe]], [[Marsden Hartley]], and others experimented with new styles, displaying a highly individualistic sensibility.
[10924950] |Major artistic movements such as the [[abstract expressionism]] of [[Jackson Pollock]] and [[Willem de Kooning]] and the [[pop art]] of [[Andy Warhol]] and [[Roy Lichtenstein]] have developed largely in the United States.
[10924960] |The tide of modernism and then [[postmodernism]] has also brought American architects such as [[Frank Lloyd Wright]], [[Philip Johnson]], and [[Frank Gehry]] to the top of their field.
[10924970] |One of the first notable promoters of the nascent American theater was impresario [[P. T. Barnum]], who began operating a lower [[Manhattan]] entertainment complex in 1841.
[10924980] |The team of [[Edward Harrigan|Harrigan and Hart]] produced a series of popular [[musical theatre|musical]] comedies in New York starting in the late 1870s.
[10924990] |In the twentieth century, the modern musical form emerged on [[Broadway theatre|Broadway]]; the songs of musical theater composers such as [[Irving Berlin]], [[Cole Porter]], and [[Stephen Sondheim]] have become [[Traditional pop music|pop standards]].
[10925000] |Playwright [[Eugene O'Neill]] won the Nobel literature prize in 1936; other acclaimed U.S. dramatists include multiple [[Pulitzer Prize for Drama|Pulitzer Prize]] winners [[Tennessee Williams]], [[Edward Albee]], and [[August Wilson]].
[10925010] |Though largely overlooked at the time, [[Charles Ives]]'s work of the 1910s established him as the first major U.S. composer in the classical tradition; other experimentalists such as [[Henry Cowell]] and [[John Cage]] created an identifiably American approach to classical composition.
[10925020] |[[Aaron Copland]] and [[George Gershwin]] developed a unique American synthesis of popular and classical music.
[10925030] |[[Choreography|Choreographers]] [[Isadora Duncan]] and [[Martha Graham]] were central figures in the creation of [[modern dance]]; [[George Balanchine]] and [[Jerome Robbins]] were leaders in twentieth-century ballet.
[10925040] |The United States has long been at the fore in the relatively modern artistic medium of [[photography]], with major practitioners such as [[Alfred Stieglitz]], [[Edward Steichen]], [[Ansel Adams]], and many others.
[10925050] |The newspaper [[comic strip]] and the [[American comic book|comic book]] are both U.S. innovations.
[10925060] |[[Superman]], the quintessential comic book [[superhero]], has become an American icon.
[10925070] |===Food=== 
[10925080] |Mainstream American culinary arts are similar to those in other Western countries.
[10925090] |[[Wheat]] is the primary [[cereal]] grain.
[10925100] |Traditional American cuisine uses ingredients such as [[Turkey (bird)|turkey]], [[white-tailed deer]] [[venison]], [[potato]]es, [[sweet potato]]es, [[maize|corn]], [[squash (plant)|squash]], and [[maple syrup]], indigenous foods employed by Native Americans and early European settlers.
[10925110] |Slow-cooked pork and beef [[barbecue]], [[crab cake]]s, [[potato chip]]s, and [[chocolate chip cookie]]s are distinctively American styles.
[10925120] |[[Soul food]], developed by African slaves, is popular around the South and among many African Americans elsewhere.
[10925130] |[[Syncretism|Syncretic]] cuisines such as [[Louisiana Creole cuisine|Louisiana creole]], [[Cajun cuisine|Cajun]], and [[Tex-Mex cuisine|Tex-Mex]] are regionally important.
[10925140] |Characteristic dishes such as [[apple pie]], [[fried chicken]], [[pizza]], [[hamburger]]s, and [[hot dog]]s derive from the recipes of various immigrants.
[10925150] |[[French fried potatoes|French fries]], Mexican dishes such as [[burrito]]s and [[taco]]s, and [[pasta]] dishes freely adapted from Italian sources are widely consumed.
[10925160] |Americans generally prefer coffee to tea.
[10925170] |Marketing by U.S. industries is largely responsible for making [[orange juice]] and [[milk]] ubiquitous breakfast beverages.
[10925180] |During the 1980s and 1990s, Americans' caloric intake rose 24%; frequent dining at [[fast food]] outlets is associated with what health officials call the American "obesity epidemic."
[10925190] |Highly sweetened [[soft drink]]s are widely popular; sugared beverages account for 9% of the average American's caloric intake.
[10925200] |===Sports=== 
[10925210] |Since the late nineteenth century, [[baseball]] has been regarded as the [[national sport]]; [[American football|football]], [[basketball]], and [[ice hockey]] are the country's three other leading professional team sports.
[10925220] |[[College football]] and [[College basketball|basketball]] also attract large audiences.
[10925230] |Football is now by several measures the most popular [[spectator sport]] in the United States.
[10925240] |[[Boxing]] and [[horse racing]] were once the most watched individual sports, but they have been eclipsed by [[golf]] and [[auto racing]], particularly [[NASCAR]].
[10925250] |[[Association football|Soccer]], though not a leading professional sport in the country, is played widely at the youth and amateur levels.
[10925260] |[[Tennis]] and many outdoor sports are also popular.
[10925270] |While most major U.S. sports have evolved out of European practices, basketball, [[volleyball]], [[skateboarding]], and [[snowboarding]] are American inventions.
[10925280] |[[Lacrosse]] and [[surfing]] arose from Native American and Native Hawaiian activities that predate Western contact.
[10925290] |Eight [[Olympic Games]] have [[United States at the Olympics|taken place in the United States]].
[10925300] |The United States has won 2,191 medals at the [[Summer Olympic Games]], more than any other country, and 216 in the [[Winter Olympic Games]], the second most.
[10930010] |<article>Verb</article>
[10930020] |For English usage of verbs see the wiki article [[English verbs]].
[10930030] |In [[syntax]], a '''verb''' is a [[word]] ([[part of speech]]) that usually denotes an action (''bring'', ''read''), an occurrence (''decompose'', ''glitter''), or a state of being (''exist'', ''stand'').
[10930040] |Depending on the [[language]], a verb may vary in form according to many factors, possibly including its [[grammatical tense|tense]], [[grammatical aspect|aspect]], [[grammatical mood|mood]] and [[grammatical voice|voice]].
[10930050] |It may also agree with the [[grammatical person|person]], [[grammatical gender|gender]], and/or [[grammatical number|number]] of some of its arguments ([[subject (grammar)|subject]], [[object (grammar)|object]], etc.).
[10930060] |==Valency== 
[10930070] |The number of arguments that a verb takes is called its ''valency'' or ''valence''.
[10930080] |Verbs can be classified according to their valency:
[10930090] |* '''[[Intransitive verb|Intransitive]]''' (valency = 1): the verb only has a [[subject (grammar)|subject]].
[10930100] |For example: "he runs", "it falls".
[10930110] |* [[transitive verb|'''Transitive''']] (valency = 2): the verb has a subject and a [[direct object]].
[10930120] |For example: "she eats fish", "Mike hunts deer".
[10930130] |* '''[[Copula|Linking]]''' (valency = 3): State of being; does not require an action.
[10930140] |The subject complements are related to subject rather than the verb.
[10930150] |It simply reports a condition or asks a questions about a condition.
[10930160] |It is impossible to have verbs with zero valency.
[10930170] |Weather verbs are often [[impersonal verb|impersonal]] (subjectless) in [[null-subject language]]s like [[Spanish language|Spanish]], where the verb ''llueve'' means "It rains".
[10930180] |In English, they require a [[dummy pronoun]], and therefore formally have a valency of 1.
[10930190] |The intransitive and transitive are typical, but the impersonal and objective are somewhat different from the norm.
[10930200] |In this sense you can see that a verb is a person, place, or thing.
[10930210] |In the objective the verb takes an object but no subject, the nonreferent subject in some uses may be marked in the verb by an incorporated dummy pronoun similar to the English weather verb (see below).
[10930220] |Impersonal verbs take neither subject nor object, as with other null subject languages, but again the verb may show incorporated dummy pronouns despite the lack of subject and object phrases.
[10930230] |Tlingit lacks a ditransitive, so the indirect object is described by a separate, extraposed clause.
[10930240] |English verbs are often flexible with regard to valency.
[10930250] |A transitive verb can often drop its object and become intransitive; or an intransitive verb can take an object and become transitive.
[10930260] |Compare:
[10930270] |* ''I moved.'' (intransitive)
[10930280] |* ''I moved the book.'' (transitive)
[10930290] |In the first example, the verb ''move'' has no grammatical object.
[10930300] |(In this case, there may be an object understood - the subject (I/myself).
[10930310] |The verb is then possibly reflexive, rather than intransitive); in the second the subject and object are distinct.
[10930320] |The verb has a different valency, but the form remains exactly the same.
[10930330] |In many languages other than English, such valency changes are not possible like this; the verb must instead be inflected for voice in order to change the valency.
[10930340] |== Copula == 
[10930350] |A [[copula]] is a word that is used to describe its subject, or to equate or liken the subject with its predicate.
[10930360] |In many languages, copulas are a special kind of verb, sometimes called ''copulative verbs'' or ''linking verbs''.
[10930370] |Because copulas do not describe actions being performed, they are usually analyzed outside the transitive/intransitive distinction.
[10930380] |The most basic copula in English is ''to be''; there are others (''remain'', ''seem'', ''grow'', ''become'', etc.).
[10930390] |Some languages (the [[Semitic language|Semitic]] and [[Slavic languages|Slavic]] families, [[Chinese language|Chinese]], [[Sanskrit language|Sanskrit]], and others) can omit or do not have the simple copula equivalent of "to be", especially in the present tense.
[10930400] |In these languages a [[noun]] and [[adjective]] pair (or two nouns) can constitute a complete sentence.
[10930410] |This construction is called ''[[zero copula]]''.
[10930420] |== Verbal noun and verbal adjective == 
[10930430] |Most languages have a number of [[verbal noun]]s that describe the action of the verb.
[10930440] |In [[Indo-European languages]], there are several kinds of verbal nouns, including [[gerund]]s, [[infinitive]]s, and [[supine]]s.
[10930450] |English has gerunds, such as ''seeing'', and infinitives such as ''to see''; they both can function as nouns; ''seeing is believing'' is roughly equivalent in meaning with ''to see is to believe.''
[10930460] |These terms are sometimes applied to verbal nouns of non-Indo-European languages.
[10930470] |In the Indo-European languages, verbal adjectives are generally called [[participle]]s.
[10930480] |English has an [[active voice|active]] participle, also called a present participle; and a [[passive voice|passive]] participle, also called a past participle.
[10930490] |The active participle of ''play'' is ''playing'', and the passive participle is ''played''.
[10930500] |The active participle describes [[noun]]s that perform the action given in the verb, e.g.
[10930510] |''I saw the playing children.''.
[10930520] |The passive participle describes nouns that have been the object of the action of the verb, e.g.
[10930530] |''I saw the played game scattered across the floor.''.
[10930540] |Other languages apply tense and aspect to participles, and possess a larger number of them with more distinct shades of meaning.
[10930550] |==Agreement== 
[10930560] |In languages where the verb is inflected, it often agrees with its primary argument (what we tend to call the subject) in person, number and/or gender.
[10930570] |English only shows distinctive agreement in the third person singular, present tense form of verbs (which is marked by adding "-s"); the rest of the persons are not distinguished in the verb.
[10930580] |Spanish inflects verbs for tense/mood/aspect and they agree in person and number (but not gender) with the subject.
[10930590] |[[Japanese language|Japanese]], in turn, inflects verbs for many more categories, but shows absolutely no agreement with the subject.
[10930600] |[[Basque language|Basque]], [[Georgian language|Georgian]], and some other languages, have ''[[polypersonal agreement]]'': the verb agrees with the subject, the direct object and even the secondary object if present.
[10940010] |<article>Web application</article>
[10940020] |In [[software engineering]], a '''Web application''' is an [[Application software|application]] that is accessed via [[Web browser]] over a network such as the [[Internet]] or an [[intranet]].
[10940030] |It is also a computer software application that is coded in a browser-supported language (such as [[HTML]], [[JavaScript]], [[Java (programming language)|Java]], etc.) and reliant on a common web browser to render the application [[executable]].
[10940040] |Web applications are popular due to the ubiquity of a [[client (computing)|client]], sometimes called a [[thin client]].
[10940050] |The ability to update and maintain Web applications without distributing and installing software on potentially thousands of client computers is a key reason for their popularity.
[10940060] |Common Web applications include [[Webmail]], online [[retail sales]], [[online auction]]s, [[wiki]]s, [[Internet forum|discussion boards]], [[Weblog]]s, [[MMORPG]]s and many other functions.
[10940070] |==History== 
[10940080] |In earlier types of [[client-server]] computing, each application had its own client program which served as its [[user interface]] and had to be separately installed on each user's [[personal computer]].
[10940090] |An upgrade to the server part of the application would typically require an upgrade to the clients installed on each user workstation, adding to the [[technical support|support]] cost and decreasing [[productivity]].
[10940100] |In contrast, Web applications dynamically generate a series of [[Web document]]s in a standard format supported by common browsers such as [[HTML]]/[[XHTML]].
[10940110] |[[Client-side scripting]] in a standard language such as [[JavaScript]] is commonly included to add dynamic elements to the user interface.
[10940120] |Generally, each individual Web page is delivered to the client as a static document, but the sequence of pages can provide an interactive experience, as user input is returned through Web [[form]] elements embedded in the page markup.
[10940130] |During the session, the Web browser interprets and displays the pages, and acts as the ''universal'' client for any Web application.
[10940140] |==Interface== 
[10940150] |The Web interface places very few limits on client functionality.
[10940160] |Through [[Java (Sun)|Java]], [[JavaScript]], [[DHTML]], [[Adobe Flash|Flash]] and other technologies, application-specific methods such as drawing on the screen, playing audio, and access to the keyboard and mouse are all possible.
[10940170] |Many services have worked to combine all of these into a more familiar interface that adopts the appearance of an operating system.
[10940180] |General purpose techniques such as [[drag and drop]] are also supported by these technologies.
[10940190] |Web developers often use client-side scripting to add functionality, especially to create an interactive experience that does not require page reloading (which many users find disruptive).
[10940200] |Recently, technologies have been developed to coordinate client-side scripting with server-side technologies such as [[PHP]].
[10940210] |[[Ajax (programming)|Ajax]], a web development technique using a combination of various technologies, is an example of technology which creates a more interactive experience.
[10940220] |==Technical considerations== 
[10940230] |A significant advantage of building Web applications to support standard browser features is that they should perform as specified regardless of the operating system or OS version installed on a given client.
[10940240] |Rather than creating clients for [[Microsoft Windows|MS Windows]], [[Mac OS X]], [[Linux|GNU/Linux]], and other [[operating system]]s, the application can be written once and deployed almost anywhere.
[10940250] |However, inconsistent implementations of the [[HyperText Markup Language|HTML]], [[Cascading Style Sheets|CSS]], [[Document Object Model|DOM]] and other browser specifications can cause problems in web application development and support.
[10940260] |Additionally, the ability of users to customize many of the display settings of their browser (such as selecting different font sizes, colors, and typefaces, or disabling scripting support) can interfere with consistent implementation of a Web application.
[10940270] |Another approach is to use [[Adobe Flash]] or [[Java applet]]s to provide some or all of the user interface.
[10940280] |Since most Web browsers include support for these technologies (usually through plug-ins), Flash- or Java-based applications can be implemented with much of the same ease of deployment.
[10940290] |Because they allow the programmer greater control over the interface, they bypass many browser-configuration issues, although incompatibilities between Java or Flash implementations on the client can introduce different complications.
[10940300] |Because of their architectural similarities to traditional client-server applications, with a somewhat "thick" client, there is some dispute over whether to call systems of this sort "Web applications"; an alternative term is "[[Rich Internet Application]]" (RIA).
[10940310] |==Structure== 
[10940320] |Though many variations are possible, a Web application is commonly structured as a [[Three-tier (computing)|three-tiered]] application.
[10940330] |In its most common form, a Web browser is the first tier, an engine using some dynamic Web content technology (such as [[Active Server Pages|ASP]], [[ASP.NET]], [[Common Gateway Interface|CGI]], [[ColdFusion]], [[Java Servlet|JSP/Java]], [[PHP]],[[embPerl]], [[Python (programming language)|Python]], or [[Ruby on Rails]]) is the middle tier, and a database is the third tier.
[10940340] |The Web browser sends requests to the middle tier, which services them by making queries and updates against the database and generates a user interface.
[10940350] |But there are some who view a web application as a Two-Tier architecture.
[10940360] |==Business use== 
[10940370] |An emerging strategy for application software companies is to provide Web access to software previously distributed as local applications.
[10940380] |Depending on the type of application, it may require the development of an entirely different browser-based interface, or merely adapting an existing application to use different presentation technology.
[10940390] |These programs allow the user to pay a monthly or yearly fee for use of a software application without having to install it on a local hard drive.
[10940400] |A company which follows this strategy is known as an [[application service provider]] (ASP), and ASPs are currently receiving much attention in the software industry.
[10940410] |==Writing Web applications== 
[10940420] |There are many [[Web application framework]]s which facilitate rapid application development by allowing the programmer to define a high-level description of the program.
[10940430] |In addition, there is potential for the development of applications on [[Internet operating system]]s, although currently there are not many viable platforms that fit this model.
[10940440] |The use of Web application frameworks can often reduce the number of errors in a program, both by making the code more simple, and by allowing one team to concentrate just on the framework.
[10940450] |In applications which are exposed to constant [[Hacker (computing)#Hacker: Intruder and criminal|hacking]] attempts on the Internet, security-related problems caused by errors in the program are a big issue.
[10940460] |Frameworks may also promote the use of best practices such as [[Post/Redirect/Get|GET after POST]].
[10940470] |==Web Application Security== 
[10940480] |The [[Web Application Security Consortium]] (WASC) and [[OWASP]] are projects developed with the intention of documenting how to avoid security problems in Web applications.
[10940490] |A [[Web Application Security Scanner]] is specialized software for detecting security problems in web applications.
[10940500] |== Applications == 
[10940510] |Browser applications typically include simple office software (word processors, spreadsheets, and presentation tools) and can also include more advanced application such as project management software, [[CAD]] Design Software, and point-of-sale applications.
[10940520] |'''Examples''' 
[10940530] |*Word processor and Spreadsheet: [http://docs.google.com Google Docs & Spreadsheets] 
[10940540] |*CRM Software: [http://www.salesforce.com/ SalesForce.com]
[10940550] |== Benefits == 
[10940560] |Browser Applications typically require little or no disk space, upgrade automatically with new features, integrate easily into other web procedures, such as email and searching.
[10940570] |They also provide cross-platform compatibility (i.e Mac or Windows) because they operate within a web browser window.
[10940580] |== Disadvantages == 
[10940590] |Standards compliance is an issue with any non-typical office document creator, which causes problems when file sharing and collaboration becomes critical.
[10940600] |Also, Browser Applications rely on application files accessed on remote servers through the internet.
[10940610] |Therefore, when connection is interrupted, the application is no longer usable.
[10940620] |[[Google Gears]] is a beta platform to combat this issue and improve the usability of Browser Applications.
[10950010] |<article>Word</article>
[10950020] |A '''word''' is a unit of [[language]] that carries [[Meaning (linguistic)|meaning]] and consists of one or more [[morpheme]]s which are linked more or less tightly together, and has a [[phonetic]]al value.
[10950030] |Typically a word will consist of a [[root (linguistics)|root]] or [[stem (linguistics)|stem]] and zero or more [[affix]]es.
[10950040] |Words can be combined to create [[phrase]]s, [[clause]]s, and [[sentence (linguistics)|sentences]].
[10950050] |A word consisting of two or more stems joined together form a [[compound (linguistics)|compound]].
[10950060] |A word combined with another word or part of a word form a [[portmanteau]].
[10950070] |==Etymology== 
[10950080] |English ''[[:wikt:word|word]]'' is directly from [[Old English]] ''word'', and has cognates in all branches of [[Germanic languages|Germanic]] ([[Old High German]] ''wort'', [[Old Norse]] ''orð'', [[Gothic language|Gothic]] ''waurd''), deriving from [[Proto-Germanic]] ''*wurđa'', continuing a virtual [[PIE]] .
[10950090] |Cognates outside Germanic include [[Baltic languages|Baltic]] ([[Old Prussian]] ''wīrds'' "word", and with different [[ablaut]] [[Lithuanian language|Lithuanian]] '' var̃das'' "name", [[Latvian language|Latvian]] ''vàrds'' "word, name") and Latin ''[[:wikt:verbum|verbum]]''.
[10950100] |The PIE stem is also found in Greek ερθει (φθεγγεται "speaks, utters" [[Hesychius of Alexandria|Hes.]] ).
[10950110] |The PIE root is "say, speak" (also found in Greek ειρω, [[rhetor|ρητωρ]]).
[10950120] |The original meaning of ''word'' is "[[utterance]], [[speech]], verbal expression".
[10950130] |Until [[Early Modern English]], it could more specifically refer to a name or title.
[10950140] |The technical meaning of "an element of speech" first arises in discussion of [[grammar]] (particularly Latin grammar), as in the prologue to [[Wyclif]]'s Bible (ca. 1400): 
[10950150] |:"This word ''autem'', either ''vero'', mai stonde for ''forsothe'', either for ''but''."
[10950160] |==Definitions== 
[10950170] |Depending on the language, words can be difficult to identify or delimit.
[10950180] |[[Dictionaries]] take upon themselves the task of categorizing a language's [[lexicon]] into [[Lemma (linguistics)|lemmas]].
[10950190] |These can be taken as an indication of what constitutes a "word" in the opinion of the authors.
[10950200] |===Word boundaries=== 
[10950210] |In [[spoken language]], the distinction of individual words is usually given by rhythm or accent, but short words are often run together.
[10950220] |See [[clitic]] for [[phonologic]]ally dependent words.
[10950230] |Spoken [[French language|French]] has some of the features of a [[polysynthetic language]]: ''il y est allé'' ("He went there") is pronounced /{{IPA|i.ljɛ.ta.le}}/.
[10950240] |As the majority of the world's languages are not written, the scientific determination of word boundaries becomes important.
[10950250] |There are five ways to determine where the word boundaries of spoken language should be placed: 
[10950260] |;Potential pause
[10950270] |:A speaker is told to repeat a given sentence slowly, allowing for pauses.
[10950280] |The speaker will tend to insert pauses at the word boundaries.
[10950290] |However, this method is not foolproof: the speaker could easily break up polysyllabic words.
[10950300] |;Indivisibility
[10950310] |:A speaker is told to say a [[Sentence (linguistics)|sentence]] out loud, and then is told to say the sentence again with extra words added to it.
[10950320] |Thus, ''I have lived in this village for ten years'' might become ''I and my family have lived in this little village for about ten or so years''.
[10950330] |These extra words will tend to be added in the word boundaries of the original sentence.
[10950340] |However, some languages have [[infix]]es, which are put inside a word.
[10950350] |Similarly, some have [[separable affix]]es; in the [[German language|German]] sentence "Ich '''komme''' gut zu Hause '''an'''," the verb ''ankommen'' is separated.
[10950360] |;Minimal free forms
[10950370] |:This concept was proposed by [[Leonard Bloomfield]].
[10950380] |Words are thought of as the smallest meaningful unit of speech that can stand by themselves.
[10950390] |This correlates phonemes (units of sound) to [[lexeme]]s (units of meaning).
[10950400] |However, some written words are not minimal free forms, as they make no sense by themselves (for example, ''the'' and ''of'').
[10950410] |;Phonetic boundaries
[10950420] |:Some languages have particular rules of [[pronunciation]] that make it easy to spot where a word boundary should be.
[10950430] |For example, in a language that regularly [[lexical stress|stresses]] the last syllable of a word, a word boundary is likely to fall after each stressed syllable.
[10950440] |Another example can be seen in a language that has [[vowel harmony]] (like [[Turkish language|Turkish]]): the vowels within a given word share the same ''quality'', so a word boundary is likely to occur whenever the vowel quality changes.
[10950450] |However, not all languages have such convenient phonetic rules, and even those that do present the occasional exceptions.
[10950460] |;Semantic units
[10950470] |:Much like the above mentioned minimal free forms, this method breaks down a sentence into its smallest [[semantics|semantic]] units.
[10950480] |However, language often contains words that have little semantic value (and often play a more grammatical role), or semantic units that are compound words.
[10950490] |;A further criterion.
[10950500] |Pragmatics.
[10950510] |As Plag suggests, the idea of a lexical item being considered a word should also adjust to pragmatic criteria.
[10950520] |The word "hello, for example, does not exist outside of the realm of greetings being difficult to assign a meaning out of it.
[10950530] |This is a little more complex if we consider "how do you do?": is it a word, a phrase, or an idiom?
[10950540] |In practice, linguists apply a mixture of all these methods to determine the word boundaries of any given sentence.
[10950550] |Even with the careful application of these methods, the exact definition of a word is often still very elusive.
[10950560] |There are some words that seem very general but may truly have a technical definition, such as the word "soon," usually meaning within a week.
[10950570] |===Orthography=== 
[10950580] |In languages with a [[writing|literary tradition]], there is interrelation between [[orthography]] and the question of what is considered a single word.
[10950590] |[[Word separator]]s (typically [[space (punctuation)|space marks]]) are common in modern orthography of languages using [[alphabetic script]]s, but these are (excepting isolated precedents) a modern development (see also [[history of writing]]).
[10950600] |In [[English orthography]], words may contain spaces if they are [[compound (linguistics)|compounds]] or [[proper noun]]s such as ''ice cream'' or ''air raid shelter''.
[10950610] |[[Vietnamese language|Vietnamese]] orthography, although using the [[Latin alphabet]], delimits monosyllabic morphemes, not words.
[10950620] |Conversely, [[synthetic language]]s often combine many lexical morphemes into single words, making it difficult to boil them down to the traditional sense of words found more easily in [[analytic language]]s; this is especially difficult for [[polysynthetic language]]s such as [[Inuktitut]] and [[Ubykh language|Ubykh]], where entire sentences may consist of single such words.
[10950630] |[[Logographic script]]s use single signs ([[character (sign)|characters]]) to express a word.
[10950640] |Most ''de facto'' existing scripts are however partly logographic, and combine logographic with phonetic signs.
[10950650] |The most widespread logographic script in modern use is the [[Chinese script]].
[10950660] |While the Chinese script has some true logographs, the largest class of characters used in modern Chinese (some 90%) are so-called pictophonetic compounds ({{lang|zh|形声字}}, {{lang|pny|Xíngshēngzì}}).
[10950670] |Characters of this sort are composed of two parts: a pictograph, which suggests the general meaning of the character, and a phonetic part, which is derived from a character pronounced in the same way as the word the new character represents.
[10950680] |In this sense, the character for most Chinese words consists of a determiner and a syllabogram, similar to the approach used by [[cuneiform script]] and [[Egyptian hieroglyphs]].
[10950690] |There is a tendency informed by orthography to identify a single Chinese character as corresponding to a single word in the Chinese language, parallel to the tendency to identify the letters between two space marks as a single word in the English language.
[10950700] |In both cases, this leads to the identification of [[compounds|compound members]] as individual words, while e.g. in [[German orthography]], compound members are not separated by space marks and the tendency is thus to identify the entire compound as a single word.
[10950710] |Compare e.g. English ''capital city'' with German ''Hauptstadt'' and Chinese 首都 (lit. [[:wikt:首|chief]] [[:wikt:都|metropolis]]): all three are equivalent compounds, in the English case consisting of "two words" separated by a space mark, in the German case written as a "single word" without space mark, and in the Chinese case consisting of two logographic characters.
[10950720] |==Morphology== 
[10950730] |In [[synthetic language]]s, a single [[word stem]] (for example, ''love'') may have a number of different forms (for example, ''loves'', ''loving'', and ''loved'').
[10950740] |However, these are not usually considered to be different words, but different forms of the same word.
[10950750] |In these languages, words may be considered to be constructed from a number of [[morpheme]]s.
[10950760] |In [[Indo-European languages]] in particular, the morphemes distinguished are 
[10950770] |*the [[root (linguistics)|root]]
[10950780] |*optional [[suffixes]]
[10950790] |*a [[desinence]].
[10950800] |Thus, the Proto-Indo-European would be analysed as consisting of 
[10950810] |#, the [[zero grade]] of the root 
[10950820] |#a root-extension (diachronically a suffix), resulting in a complex root 
[10950830] |#The [[thematic suffix]] 
[10950840] |#the [[neuter gender]] nominative or accusative singular desinence .
[10950850] |==Classes== 
[10950860] |[[Grammar]] classifies a language's lexicon into several groups of words.
[10950870] |The basic bipartite division possible for virtually every [[natural language]] is that of [[noun]]s vs. [[verb]]s.
[10950880] |The classification into such classes is in the tradition of [[Dionysius Thrax]], who distinguished eight categories: noun, verb, [[adjective]], [[pronoun]], [[preposition]], [[adverb]], [[conjunction]], [[interjection]].
[10950890] |In Indian grammatical tradition, [[Panini]] introduced a similar fundamental classification into a nominal (nāma, suP) and a verbal (ākhyāta, tiN) class, based on the set of desinences taken by the word.
[10960010] |<article>WordNet</article>
[10960020] |'''WordNet''' is a [[semantic lexicon]] for the [[English language]].
[10960030] |It groups English words into sets of synonyms called ''[[synsets]]'', provides short, general definitions, and records the various [[semantic]] relations between these [[synonym]] sets.
[10960040] |The purpose is twofold: to produce a combination of [[dictionary]] and [[thesaurus]] that is more intuitively usable, and to support automatic text analysis and [[artificial intelligence]] applications.
[10960050] |The database and software tools have been released under a [[BSD License|BSD style license]] and can be downloaded and used freely.
[10960060] |The [[database]] can also be browsed [[online]].
[10960070] |WordNet was created and is being maintained at the Cognitive Science Laboratory of [[Princeton University]] under the direction of [[psychology]] [[professor]] [[George Armitage Miller|George A. Miller]].
[10960080] |Development began in [[1985]].
[10960090] |Over the years, the project received about $3 million of funding, mainly from government agencies interested in [[machine translation]].
[10960100] |In recent years, Dr. [[Christiane Fellbaum]] has overseen the development of WordNet.
[10960110] |== Database contents == 
[10960120] |[[As of 2006]], the database contains about 150,000 words organized in over 115,000 [[synsets]] for a total of 207,000 word-sense pairs; in [[data compression|compressed]] form, it is about 12 [[megabyte]]s in size.
[10960130] |WordNet distinguishes between [[noun]]s, [[verb]]s, [[adjective]]s and [[adverb]]s because they follow different grammatical rules.
[10960140] |Every synset contains a group of synonymous words or [[collocation]]s (a ''collocation'' is a sequence of words that go together to form a specific meaning, such as "[[carpool|car pool]]"); different senses of a word are in different synsets.
[10960150] |The meaning of the synsets is further clarified with short defining ''glosses'' (Definitions and/or example sentences).
[10960160] |A typical example synset with gloss is:
[10960170] |: good, right, ripe -- (most suitable or right for a particular purpose; "a good time to plant tomatoes"; "the right time to act"; "the time is ripe for great sociological changes")
[10960180] |Most synsets are connected to other synsets via a number of semantic relations.
[10960190] |These relations vary based on the type of word, and include: 
[10960200] |* [[Noun]]s
[10960210] |**''[[hypernym]]s'': ''Y'' is a hypernym of ''X'' if every ''X'' is a (kind of) ''Y'' (''canine'' is a hypernym of ''dog'')
[10960220] |**''[[hyponym]]s'': ''Y'' is a hyponym of ''X'' if every ''Y'' is a (kind of) ''X'' (''dog'' is a hyponym of ''canine'')
[10960230] |**''coordinate terms'': ''Y'' is a coordinate term of ''X'' if ''X'' and ''Y'' share a hypernym (''wolf'' is a coordinate term of ''dog'', and ''dog'' is a coordinate term of ''wolf'')
[10960240] |**''[[holonymy|holonym]]'': ''Y'' is a holonym of ''X'' if ''X'' is a part of ''Y'' (''building'' is a holonym of ''window'')
[10960250] |**''[[meronymy|meronym]]'': ''Y'' is a meronym of ''X'' if ''Y'' is a part of ''X'' (''window'' is a meronym of ''building'')
[10960260] |* [[Verb]]s
[10960270] |**''hypernym'': the verb ''Y'' is a hypernym of the verb ''X'' if the activity ''X'' is a (kind of) ''Y'' (''travel'' is an hypernym of ''movement'')
[10960280] |**''troponym'': the verb ''Y'' is a troponym of the verb ''X'' if the activity ''Y'' is doing ''X'' in some manner (''to lisp'' is a troponym of ''to talk'')
[10960290] |**''entailment'': the verb ''Y'' is entailed by ''X'' if by doing ''X'' you must be doing ''Y'' (''to sleep'' is entailed by ''to snore'')
[10960300] |**''coordinate terms'': those verbs sharing a common hypernym (''to lisp'' and ''to yell'')
[10960310] |* [[Adjective]]s
[10960320] |**''related nouns''
[10960330] |**''similar to''
[10960340] |**''participle of verb''
[10960350] |* [[Adverb]]s
[10960360] |**''root adjectives''
[10960370] |While semantic relations apply to all members of a synset because they share a meaning but are all mutually [[synonym]]s, words can also be connected to other words through lexical relations, including [[antonym]]s (opposites of each other) and derivationally related, as well.
[10960380] |WordNet also provides the ''polysemy count'' of a word: the number of synsets that contain the word.
[10960390] |If a word participates in several synsets (i.e. has several senses) then typically some senses are much more common than others.
[10960400] |WordNet quantifies this by the ''frequency score'': in which several sample texts have all words semantically tagged with the corresponding synset, and then a count provided indicating how often a word appears in a specific sense.
[10960410] |The morphology functions of the software distributed with the database try to deduce the [[lemma (linguistics)|lemma]] or [[root (linguistics)|root]] form of a [[word]] from the user's input; only the root form is stored in the database unless it has irregular inflected forms.
[10960420] |== Knowledge structure == 
[10960430] |Both nouns and verbs are organized into hierarchies, defined by hypernym or ''IS A'' relationships.
[10960440] |For instance, the first sense of the word ''dog'' would have the following hypernym hierarchy; the words at the same level are synonyms of each other: some sense of ''dog'' is synonymous with some other senses of ''domestic dog'' and ''Canis familiaris'', and so on.
[10960450] |Each set of synonyms (''synset''), has a unique index and shares its properties, such as a gloss (or dictionary) definition.
[10960460] |dog, domestic dog, Canis familiaris => canine, canid => carnivore => placental, placental mammal, eutherian, eutherian mammal => mammal => vertebrate, craniate => chordate => animal, animate being, beast, brute, creature, fauna => ...
[10960470] |At the top level, these hierarchies are organized into [[base types]], 25 primitive groups for nouns, and 15 for verbs.
[10960480] |These groups form ''lexicographic files'' at a maintenance level.
[10960490] |These primitive groups are connected to an abstract root node that have, for some time, been assumed by various applications that use WordNet.
[10960500] |In the case of adjectives, the organization is different.
[10960510] |Two opposite 'head' senses work as binary poles, while 'satellite' synonyms connect to each of the heads via synonymy relations.
[10960520] |Thus, the hierarchies, and the concept involved with lexicographic files, do not apply here the same way they do for nouns and verbs.
[10960530] |The network of nouns is far deeper than that of the other parts of speech.
[10960540] |Verbs have a far ''bushier'' structure, and adjectives are organized into many distinct clusters.
[10960550] |Adverbs are defined in terms of the adjectives they are derived from, and thus inherit their structure from that of the adjectives.
[10960560] |== Psychological justification == 
[10960570] |The goal of WordNet was to develop a system that would be consistent with the knowledge acquired over the years about how human beings process language.
[10960580] |[[Anomic aphasia]], for example, creates a condition that seems to selectively encumber individuals' ability to name objects; this makes the decision to partition the parts of speech into distinct hierarchies more of a principled decision than an arbitrary one.
[10960590] |In the case of [[hyponym]]y, psychological experiments revealed that individuals can access properties of nouns more quickly depending on when a characteristic becomes a defining property.
[10960600] |That is, individuals can quickly verify that ''canaries can sing'' because a canary is a songbird (only one level of hyponymy), but requires slightly more time to verify that ''canaries can fly'' (two levels of hyponymy) and even more time to verify ''canaries have skin'' (multiple levels of hyponymy).
[10960610] |This suggests that we too store semantic information in a way that is much like WordNet, because we only retain the most specific information needed to differentiate one particular concept from similar concepts.
[10960620] |== WordNet as an ontology == 
[10960630] |The hypernym/hyponym relationships among the noun synsets can be interpreted as specialization relations between conceptual categories.
[10960640] |In other words, WordNet can be interpreted and used as a lexical [[ontology (computer science)|ontology]] in the [[computer science]] sense.
[10960650] |However, such an ontology should normally be corrected before being used since it contains hundreds of basic semantic inconsistencies such as (i) the existence of common specializations for exclusive categories and (ii) redundancies in the specialization hierarchy.
[10960660] |Furthermore, transforming WordNet into a lexical ontology usable for knowledge representation should normally also involve (i)&nbsp;distinguishing the specialization relations into subtypeOf and instanceOf relations, and (ii)&nbsp;associating intuitive unique identifiers to each category.
[10960670] |Although such corrections and transformations have been performed and documented as part of the [http://www.webkb.org/doc/wn/ integration of WordNet&nbsp;1.7 into the cooperatively updatable knowledge base of WebKB-2], most projects claiming to re-use WordNet for knowledge-based applications (typically, knowledge-oriented information retrieval) simply re-use it directly.
[10960680] |== Limitations == 
[10960690] |Unlike other dictionaries, WordNet does not include information about [[etymology]], pronunciation and the forms of [[irregular verb]]s and contains only limited information about usage.
[10960700] |The actual lexicographical and semantical information is maintained in ''lexicographer files'', which are then processed by a tool called ''grind'' to produce the distributed database.
[10960710] |Both grind and the lexicographer files are freely available in a separate distribution, but modifying and maintaining the database requires expertise.
[10960720] |Though WordNet contains a sufficient wide range of common words, it does not cover special domain vocabulary.
[10960730] |Since it is primarily designed to act as an underlying database for different applications, those applications cannot be used in specific domains that are not covered by WordNet.
[10960740] |== Applications in Information Systems == 
[10960750] |WordNet has been used for a number of different purposes in information systems, including word sense disambiguation, information retrieval, automatic text classification, automatic text summarization, and even automatic crossword puzzle generation.
[10960760] |A project at [[Brown University]] started by [[Jeff Stibel]], [[James A. Anderson]], [[Steve Reiss]] and others called [[Applied Cognition Lab]] created a disambiguator using WordNet in 1998.
[10960770] |The project later morphed into a company called [[Simpli]], which is now owned by [[ValueClick]].
[10960780] |George Miller joined the Company as a member of the Advisory Board.
[10960790] |Simpli built an Internet search engine that utilized a knowledgebase principally based on WordNet to disambiguate and expand keywords and synsets to help retrieve information online.
[10960800] |WordNet was expanded upon to add increased dimensionality, such as intentionality (used for x), people ([[Albert Einstein]]) and colloquial terminology more relevant to Internet search (i.e., blogging, ecommerce).
[10960810] |[[Neural network]] algorithms searched the expanded WordNet for related terms to disambiguate search keywords (Java, in the sense of coffee) and expand the search synset (Coffee, Drink, Joe) to improve search engine results.
[10960820] |Before the company was acquired, it performed searches across search engines such as [[Google]], [[Yahoo]]!, [[Ask.com]] and others.
[10960830] |Another prominent example of the use of WordNet is to determine the [[semantic similarity|similarity]] between words.
[10960840] |Various algorithms have been proposed, and these include considering the distance between the conceptual categories of words, as well as considering the hierarchical structure of the WordNet ontology.
[10960850] |A number of these WordNet-based word similarity algorithms are implemented in a [[Perl]] package called [http://www.d.umn.edu/~tpederse/similarity.html WordNet::Similarity].
[10960860] |== Interfaces == 
[10960870] |Princeton maintains a list of [http://wordnet.princeton.edu/links related projects] that includes links to some of the widely used [[application programming interface]]s available for accessing WordNet using various programming languages and environments.
[10960880] |Other interfaces include the following: 
[10960890] |* [http://www.defineitfast.com/find/ WordNet on Ajax::DefineItFast.com] allows users to browse Wordnet 3.0 using an [[Ajax (programming)|ajax]] interface.
[10960900] |* The [http://mfwallace.googlepages.com/jawbone.html Jawbone] project provides a [[Java (programming language)|Java]] API to the WordNet 2.1 and 3.0 data.
[10960910] |The source code is released under the [[MIT license]].
[10960920] |* The [http://nltk.sourceforge.net/ Natural Language Toolkit] provides a [[Python (programming language)|Python]] API to the WordNet 3.0.
[10960930] |* [http://search.cpan.org/perldoc?Lingua::Wordnet Lingua::Wordnet] provides a [[Perl]] interface to WordNet.
[10960940] |* [http://search.cpan.org/perldoc?WordNet::Similarity WordNet::Similarity] Perl module for computing measures of semantic relatedness.
[10960950] |* [http://www.cozyenglish.com/dictionary Dictionary::CozyEnglish] implemented a WordNet 3.0 interface that integrates with [[WordPress]].
[10960960] |Blog and website owners can embed this API via a set of HTML code.
[10960970] |* The [http://www.visualthesaurus.com/ Visual Thesaurus] is a subscription-based commercial application that presents WordNet data through an innovative and user-friendly interface.
[10960980] |* [[WordWeb]] is an extended dictionary based on WordNet, also available commercially as [http://wordweb.info/developer/SQL.html SQL tables] for use in other applications.
[10960990] |Includes many additional terms, derived forms and pronunciations.
[10961000] |* [http://www.ug.it.usyd.edu.au/~smer3502/assignment3/form.html Visual representation of WordNet] - interface which attempts to visualise the relations.
[10961010] |== Related projects == 
[10961020] |The [[EuroWordNet]] project has produced WordNets for several European languages and linked them together; these are not freely available however.
[10961030] |The [[Global Wordnet]] project attempts to coordinate the production and linking of "wordnets" for all languages.
[10961040] |[[Oxford University Press]], the publisher of the [[Oxford English Dictionary]], has voiced plans to produce their own online competitor to WordNet.
[10961050] |The [[eXtended WordNet]] is a project at the [[University of Texas at Dallas]] which aims to improve WordNet by semantically parsing the glosses, thus making the information contained in these definitions available for automatic knowledge processing systems.
[10961060] |It is also freely available under a license similar to WordNet's.
[10961070] |The [[GCIDE]] project produces a dictionary by combining a [[public domain]] ''[[Webster's Dictionary]]'' from [[1913]] with some WordNet definitions and material provided by volunteers.
[10961080] |It is released under the [[copyleft]] license [[GNU General Public License|GPL]].
[10961090] |WordNet is also commonly re-used via mappings between the WordNet categories and the categories from other ontologies.
[10961100] |Most often, only the top-level categories of WordNet are mapped.
[10961110] |However, the authors of the [[Suggested Upper Merged Ontology|SUMO]] ontology have produced a mapping between all of the WordNet synsets, (including nouns, verbs, adjectives and adverbs), and [[SUMO class]]es.
[10961120] |The most recent addition of the mappings provides links to all of the more specific terms in the MId-Level Ontology (MILO), which extends SUMO.
[10961130] |[[OpenCyc]] has 12,000 terms linked to WordNet synonym sets.
[10961140] |In most works that claim to have integrated WordNet into other ontologies, the content of WordNet has not simply been corrected when semantic problems have been encountered; instead, WordNet has been used as an inspiration source but heavily re-interpreted and updated whenever suitable.
[10961150] |This was the case when, for example, the [http://citeseer.ist.psu.edu/oltramari02restructuring.html top-level ontology of WordNet was re-structured] according to the [[OntoClean]] based approach or when WordNet was used as a primary source for constructing the lower classes of the SENSUS ontology.
[10961160] |[[FrameNet]] is a project similar to WordNet.
[10961170] |It consists of a lexicon which is based on annotating over 100,000 sentences with their semantic properties.
[10961180] |The unit in focus is the ''lexical frame'', a type of state or event together with the properties associated with it.
[10961190] |An independent project titled [http://wordnet.cemetech.net wordNet] with an initial lowercase w is an ongoing project to links words and phrases via a custom [[Web crawler]].
[10961200] |[[Lexical markup framework]] (LMF) is a work in progress within [[ISO/TC37]] in order to define a common standardized framework for the construction of lexicons, including WordNet.
[10961210] |The [http://www.ceid.upatras.gr/Balkanet/ BalkaNet] project has produced WordNets for six European languages (Bulgarian, Czech, Greek, Romanian, Turkish and Serbian).
[10961220] |For this project, freely available XML-based WordNet editor was developed.
[10961230] |This editor - [http://nlp.fi.muni.cz/projekty/visdic/ VisDic] - is not in active development anymore, but is still used for the creation of various WordNets.
[10961240] |Its successor, [http://deb.fi.muni.cz DEBVisDic], is client-server application and is currently used for the editing of several WordNets (Dutch in Cornetto project, Polish, Hungarian, several African languages, Chinese).