Words of American origin, or Americanisms, are rather hard group to define. For the sake of sanity, the words listed below are generally words that were dragged into the English language by people living in what would become the area currently occupied by the USA, including a large number of Native American words. Some of these Americanisms have spread to become used across much of the English speaking world, but many of them are still largely limited to America.

These are arranged by the date they first appeared in print, so many were probably in use for at least a few years before the date given. Oh, and for anyone not American, I should mention that many words appear on this list that are no longer in common usage.

Neologism Comments First appeared
MoccasinProbably from Powhatan.1610s
MooseFrom a Native American language. 1610s
OpossumAlso possum, from Powhatan. 1610s
PersimmonPowhatan.1610s
RaccoonPowhatan1610s
TomahawkPowhatan.1610s
Pow wowProbably Narragansett; at this point retained original sense of shaman. Current sense from 1812. 1620s
CreekTo mean a 'small stream'; previous to this it meant an inlet. 1620s
HominyProbably from Powhatan.1629
PapooseAlgonquin. 1630s
SkunkAlgonquian.1630s
WampumAlgonquian.1630s
Passageway1640s
HelpTo refer to servants, and later, employees in general. 1640s
Cranberry1640s
Birchbark1640s
Chomp1640s
SquashThe vegetable; from Narraganset language.1640s
RaisingTo refer to erecting a building, e.g., 'barn raising'. 1650s
Huckleberry 1660s
LumberMeaning 'wood cut into planks'.1660s
BlazeA cut made on a tree to mark a trail; the verb form (as in 'blaze a trail') appeared in 1750.1660s
Hickory1670s
WoodchuckFrom Cree, originally meant a marten.1670s
TerrapinAlgonquian.1670s
NubbinAt this time it referred specifically to a stunted ear of corn. 1690s
Sleigh1703
Cookie1703
DoryA small, flat-bottomed boat.1709
TicketTo refer to a political parties list of candidates. 1711
Catnip1712
Pecan From Cree for 'nut'. 1712
Lacrosse1718
Killdeer1731
Gubernatorial1734
Applesauce1739
Johnny-cake 1739
Hoe-cake1745
Chore1751
Chowder "A favorite dish in New England, made of fish, pork, onions, and biscuit stewed together. Cider and champagne are sometimes added." 1751
Quahog Appeared as 'poquauhock' as early as 1643. 1753
Riffle 1754
StoopThe raised platform in front of a house. 1755
Collard At this time referred to cabbage. 1755
Coyote 1759
Lengthy A much disparaged heathen neologism. A proper Englishman used 'long'. 1759
Totem Algonquian. 1760
Caucus 1763
Banjo 1764
Canebreak 1770
Underbrush In England they used 'undergrowth'. 1775
Nohow 1775
CussNoun: 'Troublesome person or animal'. The verb 'to cuss' did not appear until 1815.1775
Eggnog 1775
Around In the sense of 'around this area', 'moving around'. In England they would say 'about', and reserve 'around' for referring to circumference. 1776
Crabby In the sense of 'grouchy'. 1776
Indian summer 1778
Americanism 1781
Appraisal 1784
RareWhen applied to meat. Originally used to refer to eggs only. 1784
Tarnation 1784
Gawk 1785
Eventuate 1788
Anti-American 1788
Federalism1788
Lobby In the political sense. 1790s
Eraser At this time the eraser was a knife for scrapping ink off the page; the rubber eraser appeared in 1858. 1790
Pemmican From Cree. 1791
Calaboose 1792
Boughten Irregular past participle of buy, now obsolete. 1793
Coleslaw 1794
Swat To hit. 1796
Oxbow A curve in a river. 1797
Spat A fight. 1804
Gavel 1805
Cruller 1805
Hydrant 1806
Suspenders1806
Dido As in 'to cut a dido'. 1807
StumpTo mean 'baffle'.1807
Lasso Verb recorded 1907, noun 1908. 1807
Rowdy As a noun. The adjectival form appeared in 1819. 1808
Grit To mean 'pluck', 'moxie'. 1808
Bushwhacker1809
Doughnut1809
Jollification 1809
General store 1810
Drug store1810
SpittoonPreviously called a 'spitting box'. 1811
Gerrymander 1812
PowwowIn current sense. Previously meant 'shaman', then 'mystical meeting'. 1812
Frontiersman 1814
HonkOriginally used for the sound a goose makes; co-opted for automobile horns in 1895. 1814
ChambrayFrom the French city Cambrai.1814
Keno 1814
Disremember 1815
Boost 1815
OrneryAt this time meant 'ordinary', 'plain', or 'ugly'. Sense of 'mean' appeared in the 1860s. 1816
Clearing To refer to an area in a forest that has been cleared of trees. 1818
Un-American1818
Citified 1819
Bobwhite The North American Partridge. 1819
Bakery Replacing 'bakehouse' 1820s
Shotgun 1821
Potpie 1823
Flunk 1823
Brash 1824
Maple syrup 1824
RileAs in 'rile up'; a variation on the proper English 'roil'.1825
Intercontinental 1825
Gouge In the sense of 'swindle'. 1826
Firewater 1826
Pod To mean a herd of whales or seals. 1827
Enthuse 1827
Mail As a verb. 1828
Splurge 1828
Cupcake1828
Siding Boarding on the side of a building. 1829
Cahoots 1829
Mosey1829
Faze 1830
Have a chip on one's shoulder 1830
Preempt1830
Hoosier 1830
Dander To mean temper. 1831
Snoop 1832
Hallway 1832
Gulch 1832
Casket To mean 'coffin'. Previously, a casket was a jewel-box or small chest. 1832
Valedictorian 1832
Horse sense 1832
Mugwump 1832
Self-made man 1832
Greased lightning 1832
Lariat 1832
Conniption 1833
Blamed In the sense of 'confounded' (as a euphemism for 'damned'). 1833
Boodle 'A crowd'; but see 1858. 1833
Goober To mean 'peanut'. 1833
Sassy Alteration of 'saucy'. 1833
Root hog or die 1834
Chipper To mean 'lively'. 1834
Poker The card game. 1834
Catawampusly An intensifier of uncertain meaning; morphed into a noun, catawampus, by 1843. 1834
Chickadee Previously known as the 'black-capped titmouse'. 1834
Schoolmarm 1834
Cute When used to mean 'pretty'. 1834
Discombobulate 1834
Graham crackers 1834
Jack o'lantern The Jack o'lantern is a English evil spirit, but the carved pumpkin is American. 1834
Induct In the sense of 'bring into the military'. 1834
GalleywestNow obsolete.1835
Huckleberry 'A person of little consequence'. Now obsolete. 1835
Clambake 1835
Jigger 1836
Sucker 'An easily fooled person'. 1836
Sectionalism 1836
Bartender 1836
Seafood 1836
Junction 'The place where two things meet'; originally used to refer to railway tracks. 1836
Bogus At this time used only for counterfeit money. 1838
Buster Originally anything large, esp. a man of great strength. 1838
Antsy 1838
Ante In poker; as a noun in 1838, and then as a verb in 1846. 1838
Knowhow 1838
Freighter To mean the ship; previously, it referred to the person loading the freight. 1839
Skeeter 1839
Bird An exceptionally clever or accomplished person. 1839
Fixings To refer to food and garnishings. 1839
Bumper Originally used for train cars, used for automobiles by 1901. 1839
Kite To write an invalid check. 1839
Hooker1840s or 1850s
Chop-chop Pidgin English, from Chinese k'wa-k'wa. 1840s
Hang In the idiom 'to get the hang of something'. 1840s
Fellowship In the religious sense; 'to hold communion with'; 'to hold fellowship with' 1840s
Root beer 1841
Bunkum To mean 'nonsense'. Before this, it was used to refer to a congressman's home district. 1841
Saloon To refer to a drinking establishment. 1841
Rubber To refer to an overshoe. 1842
Catawampus A hobgoblin; meaning has changed multiple times, see 1864, 1873. 1843
Curlicue 1843
Chewing gum 1843
Craps The dice game. 1843
Bicentennial 'Bicentenary' seems to have been the more popular term in England. 1843
Bonanza 1844
Billionaire 1844
Amish 1844
Deckhand 1844
Chaps Cowboy chaps, that is. 1844
Inchworm 1844
Loco 1844
Incommunicado 1844
Blazer 'Something that attracts attention'. The meaning of a jacket is British university slang from 1880. 1845
Knock your socks off 1845
Josh Meaning 'to make fun of', 'to banter'. 1845
Bedspread 1845
Bender 'Drinking bout'; perhaps from the Scottish bender, meaning a heavy drinker. 1846
Snollygoster Now obsolete. 1846
Fizzle To refer to a failure, and latter, to the sound. American college slang. (Before this time it referred to passing gas without sound). 1846
Euchre 1846
Road-runner To refer to the long-tailed crested desert cuckoo. 1847
Doorknob 1847
Bat In the sense of 'to bat an eye'. 1847
Guy Obviously, an English word, but at this time Americans started using it to mean a 'fellow', with no pejorative sense. 1847
Sequoia In honor of Sequoya (a.k.a. George Guess), the developer of written Cherokee. 1847
Logy 1848
Slowpoke 1848
Sorehead 1848
Stag Referring to a males-only event (as in 'stag party'). 1848
Billy To refer to a bugler's crowbar; sense of billy club first used in 1856 1848
Hooky 1848
Woodsy 1848
Boxcar 1856
Indeedy 1856
Chow 1856
Landslide The English used 'landslip'. 1856
Greaser Derogatory slang for Mexicans. 1849
Katzenjammer A hangover. 1849
Grocery To refer to a grocer's shop; the word had long been used to refer to the wares the grocer sells. In America these wares started to use the plural, groceries. 1850s
Voodoo 1850
Buddy 1850
SawbuckTo mean a ten dollar bill, from the Roman numeral 'X', which looked like a sawbuck for cutting wood. 1850
Chaparral 1850
Jerky 1850
Abalone 1850
Crybaby 1851
Cholo 1851
Doggone 1851
Logjam 1851
Eat crow 1851
Rocker Short for rocking chair. 1852
Catch some zees1852
Lickety-split 1852
Mailbox To refer to what the English were calling letterboxes. 1853
Loony 1853
One-horse town 1853
Decolonization 1853
Checklist 1853
Keep your eyes peeled 1853
Shanghai To drug a man and force him to work as a sailor. 1854
Run across 'Encounter', 'meet'. 1855
Ginger-snap 1855
Jigsaw To refer to a 'vertical reciprocating saw'. 1855
Spondulics 'Money'. Spread to England and continued to be used there after it became obsolete in American English. 1856
Billy As in 'billy club' first used in 1848 to refer to a bugler's crowbar. 1856
Plug-ugly 1856
Bloviate 1857
Ship To refer to transporting goods by things that aren't ships -- railways, etc. 1857
Tie To refer to railway ties. 1857
Whangdoodle 1858
Flurry To refer to snow. 1858
Boodle 'Graft money'; but see 1833. 1858
Buzz-saw 1858
Postgraduate 1858
Cobbler To refer to a deep-dish fruit pie. 1859
Streetcar 1859
Bubba 1860s
Peel it'Run away fast', later to morph into 'peel out'.1860
Jack up This appears to be the first use of 'jack' in a verb form in English. 1860
Factionalism 1860
Run Meaning 'to be in charge of'. 1861
About face 1861
Homemaker 1861
Skedaddle Civil war slang 1861
Blowfish 1862
Choosy 1862
Lollygag 1862
Hindsight 1862
Shortage 1862
Shebang Civil War slang, originally meant a hut or shed; phrase 'the whole shebang' first recorded 1869. 1862
Biz Short for 'business'.1862
Old Glory 1862
Barbed wire 1863
Deadbeat As a noun to describe a person. In England "dead beat" meant 'worn out', 'used up'. 1863
On the up-and-up 1863
Issuance 1863
JackrabbitShort for jackass-rabbit.1863
Bum To loaf and beg. The noun appeared in 1864. 1863
Cakewalk 1863
CatawampusMeaning 'askew', but see 1834, 1843, and 1873.1864
Itemize 1864
Doughboy1864
Scrimshaw1864
Gatling gun 1864
Boardwalk 1864
Draftee1864
Surefire1864
Miscegenation 1864
Poppycock 1865
Walkway 1865
Escapee 1865
BouncerTo mean someone that throws rowdy folk out of a bar; in England, this job was referred to as a 'chucker out'.1865
Burglarize First written reference is a Canadian publication, mocking the American usage. 1865
GraftTo mean 'corruption'. 1865
Commuter1865
Hunky-dory1866
Jamboree1866
NogginTo mean a person's head.1866
Mom1867
Off-colorTo refer to something, esp. a joke, of questionable taste.1867
Winery1867
Ku Klux Klan1867
To feel in your bones1867
Carpetbagger1868
JokerTo refer to the playing card. 1868
Champ1868
Stink-bug1869
HuskyTo mean 'strong', 'tough'. 1869
Underclassman1869
Oodles1869
Unicycle1869
Hooter As in "I don't care a hooter for him." Later shortened to 'hoot' in the 1890s. 1870s
BushedTo mean tired. 1870
Hoodoo1870
Fuddy-duddy1871
Fraidy-cat1871
DiveTo mean an 'undesirable bar'. 1871
Gym1871
BoomAn increase or success, e.g. 'boom town', 'boom and bust'. 1871
GanglyThe English used gangling. 1872
Well-heeled1872
DivvyOriginally a noun ('a share'), noun appearing circa 1877.1872
Nonpartisan1872
CatawampusMeaning 'in a diagonal position', 'crooked', used esp. in North Carolina; but see 1834, 1843, and 1864.1873
High-roller1873
HarmonicaFor a mouth organ. Benjamin Franklin had originally coined the word in 1762 to refer to his glass harmonica. 1873
HikeTo mean 'hitch up one's pants'. 1873
StraightAs in 'undiluted'; 'a straight whiskey'.1874
ScoopMeaning 'to be the first to get a news story'.1874
Expansionist1874
PlumbingTo refer to water and drainage pipes; coined because they were sealed with lead. 1875
Grubstake1876
Pulchritudinous1877
Hoopla1877
TonyTo mean 'of a high tone' or 'affecting social elegance'.1877
JointA location, as in 'case the joint' (Note: 'case' was not used in that sense until 1915).1877
BootAs a verb meaning 'to kick'.1877
BangsThe term bang-tail had already been used in reference to trimmed horses' tails since 1870. 1878
StuntMeaning a trick or attempt to show off. College sports slang.1878
Shack1878
BugTo refer to a glitch in a machine, attributed to Thomas Edison; Grace Hopper may have introduced this term in computing in 1947, when she referred to 'debugging' a computer. 1878
CrookTo mean thief or swindler. 1879
Sideburns1880
Horn inCowboy slang.1880
HeeledTo have money; cowboy slang. 1880
Uppity1880
Quitter1881
Credit union1881
TwisterTo mean 'tornado'. 1881
GallTo refer to a character trait. 1882
RustleTo mean 'steal', as in 'rustle cattle'. 'Rustler' appeared this year as well. 1882
Bike1882
Hand-outHobo slang.1882
Pink-eye1882
HelloThis form was popularized with the invention of the Telephone. The original form was most likely holla, bu the English (and Americans) used any number of alternative forms.1883
Incinerator1883
Geoduck1883
Kazoo1884
Copycat1884
Forked tongue1885
Chop suey1885
GrowlerTo mean a 'vessel for beer'. 1885
Hideout1885
SwipeTo mean 'steal'; prison slang.1885
SouthpawBaseball slang.1885
DriveTo mean an event to raise money for a cause. 1885
Kahuna1886
Co-ed1886
Razzle-dazzle1886
LeftyBaseball slang.1886
LinotypeOriginally trademarked. 1886
Civics1886
RatsAs an interjection/exclamation.1886
HaberdasherTo refer specifically to someone who sells men's clothing. 1887
JagA period of unrestrained activity.1887
Dogie1887
BeefTo mean 'to complain'. 1888
BellyacheTo mean 'complain'.1888
TabTo mean 'account' (running tab) or 'bill'.1888
Yep1889
BootlegTo refer to illegal goods -- originally, specifically liqueur.1889
Down-and-out1889
Hobo1889
Bleachers1889
ConTo refer to a cheat or trick.1889
Gyp1889
RootTo cheer for a team. 1889
Electrocution1889
Buckaroo1889
Race riot1889
DelicatessenFrom the German delikatessen.1889
MathShort for mathematics. The British 'maths' appeared 1911.1890
DinerTo refer to the railway car, rather than the person eating. In 1935 American's additionally invented the restaurant intended to look like a dining car. 1890
CinchTo mean 'to make certain'. 1891
PrezShortening of president.1892
Basketball1892
Bench-warmer1892
Tromp1892
Speedway1892
Smack-dab1892
Ferris wheel1893
MidwayTo refer to the central avenue of a fairground; probably spread quickly, as it was first recorded during the Worlds Columbian Exposition in Chicago. 1893
Gooey1893
Cold feet1893
Crime wave1893
PromShort for 'promenade'. 1894
Mortician1895
Toilet For a lavatory or latrine. 1895
FudgeFor the candy. 1895
Simoleon1895
FoxyTo refer to an attractive woman.1895
ShyTo mean 'lacking', 'falling short'. 1895
Gabfest1895
Druthers1895
Feisty1896
Wise guy1896
Gangster1896
Woozy1897
Sundae1897
Salisbury steak1897
Sissified1897
One-trick pony1897
Chesty'Aggressive', 'self-assured'. The sense of having large breasts was not recorded until 1955. 1898
Yellow journalism1898
Chiropractic1898
GookMilitary slang. 1899
Seven-year itch1899
Jeepers1900
PickledTo mean 'drunk'.1900
YapAs a term for one's mouth. 1900
EscalatorOriginally a trade name (Otis Elevator Co.).1900
Banana republic1901
Kike1901
Lollapalooza1901
YeggHobo slang.1901
Wrong side of the tracks1901
Sidekick1901
ExecutiveTo refer to a high-ranking businessman. 1902
Smidge1902
Buttinski1902
Foolproof1902
French fries1903
OutageA play on 'shortage'. 1903
Goo1903
A la modeTo mean 'with ice cream on top'. 1903
Breezeway1904
Underpass1904
FlophouseHobo slang. 1904
Mulligan stewHobo slang.1904
Internist1904
GasAs short for gasoline.1905
BeatTo mean 'tired'.1905
Kitchenette1905
Humdinger'A beautiful woman'.1905
BeanTo mean 'head'; used to mean 'to hit in the head' by 1910.1905
Aggie1905
GriftThe noun appeared in 1906, the verb form in 1915.1906
Bellhop1906
JitneySaid to be named from a slang term for a nickel, which was the standard fare.1906
Tarp1906
Luncheonette1906
Wisecrack1906
Glom1907
Celeb1908
Hep'Hepcat' not used until 1938. 1908
CokeShort for cocaine. 1908
Temp1909
Boob'Stupid person'.1909
Dilly1909
Lemon'A worthless thing'.1909
Kewpie1909
Emote1909
Lone wolf1909
BoondocksMilitary slang, from Tagalog. 1910s
Go-getter1910
RunoffIn the electoral sense.1910
MajorIn the sense of 'major in a subject'. 1910
Jinx1911
CorsageTo refer to a small bunch of flowers worn on the bodice; before this it referred to the body of a dress. 1911
Jaywalking1912
CoverageTo refer to insurance; previously referred to an entry fee.1912
Wop1912
BugIn 1912 a British lexicographer noted that Americans had expanded the use of the word 'bug' to include what an Englishman would refer to as beetles. 1912
MarqueeTo refer to the structure over the entrance to a hotel or theater. 1912
Yes-man1912
Keep up with the Joneses1913
Jazz1913
Portsider'Lefthanded person', baseball slang.1913
TruckTo refer to a motorized vehicle for carrying heavy loads. 1913
Row-house1913
Faggot'Male homosexual'1914
Feeb1914
JakeTo mean 'fine', as in 'everything is jake'. 1914
Doohickey1914
FacialTo mean a beauty treatment. 1914
Stock-carFor a race car.1914
Grand'1000 dollars'1915
Bullshit1915
CaseExamine, as in 'case the joint'.1915
Big houseTo refer to prison. 1915
Country mile1915
City slicker1916
R.O.T.C.1916
FrankShort for frankfurter.1916
Goof1916
Realtor1916
Wooden nickel1916
Duffel bag1917
Toot sweet1917
Gandy dancerA railroad maintenance worker.1918
DumbbellTo mean a stupid person.1918
Smacker'Money'1918
Burp1932
DripTo mean 'nonsense'. Came to mean 'dull person' in 1932. 1919
Dunk1919
Stick one's neck out1919
Basket caseAt this time it referred to quadriplegics. 1919
Widget1920s
Moolah1920s
FannyTo refer to a woman's behind. Probably comes directly from a corruption of the British meaning. 1920
LaneTo refer to a single lane on a marked road. 1921
Bulldyker'One who engages in lesbian activities'; see 1931, dyke. 1921
Patootie1921
Checkup1921
Hooey 1922
BaloneyTo mean 'nonsense'. 1922
TizzyAs in the phrase, 'in a tizzy'.1922
Jeez1922
Frappe1922
Hijack1922
Beautician1924
Wow1924
Pooch1924
Malarkey1924
Outdoorsman1924
Flub1924
GimpyHobo slang1925
Jitters1925
OfaySlang for a white person. 1925
YearbookTo refer specifically to a book of the students within a grade or academic setting.1926
Finagle1926
Gimmick1926
Pitchman1926
Levis1926
Preemie1927
Prankster1927
HeistAs a verb. Noun recorded in 1936.1927
MarblesAs in 'to lose one's marbles', i.e., go crazy; may be from French meubles, 'furniture', AKA, belongings. 1927
WingdingOriginally hobo slang to refer to faking a seizure; used by 1949 to mean a celebration. 1927
Do-gooderPreviously the term was 'do-good'. 1927
Jive1928
BreezeTo refer to something easy.1928
TangleAs in 'to mess with'. 1928
Toboggan1929
Combo1929
Overpass1929
Seeing Eye dogThe term was originally trademarked by Seeing Eye Inc. of New Jersey.1929
BoobsShort for the much older 'boobies'.1929
FuzzTo refer to the police. 1929
Big shotThe phrase 'great shot' was used in the same sense previous to this.1929
BarrelUsed to mean 'to move quickly along'.1930
MoxieFrom the name of a brand of beer.1930
Cookout1930
Gobo1930
Down homeUsed as an adjective.1931
Dyker For 'lesbian'; see 1921, bulldyker. 1931
Blacktop1931
The American dream1931
Jitter and Jittery1931
CornyTo mean 'old-fashioned' or 'sentimental. 1932
Half-assed1932
GunkTrademarked name for liquid soap; entered into common usage 1949.1932
Nertz American college slang 1932
Supermarket1933
MainlineAs in 'to inject drugs directly into the vein'. 1933
Escapism1933
Unfazed1933
Customize1934
Po-face1934
Reet'Right'; 'cool', Jazz slang. Now obsolete. 1934
Greaseball 1934
NeatTo mean 'cool'.1934
John Q. Public1934
Panelist1935
Boondoggle1935
Shack up1935
CreepTo mean 'a despicable person'.1935
JerkA tedious, useless person. Carnival slang.1935
QuintTo mean quintuplet. 1935
Desegregation1935
Icky1935
MarinaIn the sense of 'a place for boats to park'.1935
Toots1936
G.I.From Government Issue; used only for equipment until 1943, when it began to be used for the soldiers themselves. 1936
BlooperFirst used in baseball for a missed catch; first used to refer to film in 1943.1937
Groovy1937
Jukebox1937
Iffy1937
Grapheme1937
Jitterbug1938
HepcatBut see 'hep', 1908. 1938
Medicine show1938
Cheeseburger1938
Pretrial1938
Senior citizen1938
Smackeroo'Money'.1939
Carport1939
Snit1939
Homeboy African American slang 1940s
Perp1940s
Hootenanny1940
Gussy'To dress up or decorate in a showy way'. Now most familiar in the phrase 'all gussied up'.1940
CrudCollege slang. 1940
Aftermarket1940
Snafu1941
Boot camp1941
Joe BlowMilitary slang.1941
Anglo'An English speaking white American'.1941
JeepAmerican Army slang.1941
DreamyTo refer to a cure boy or girl. 1941
Second-guess1941
Inductee1941
ClassifiedTo refer to secret government documents.1941
SmackTo mean 'heroin'.1942
Cop out1942
Zoot suit1942
Gung hoThe motto of Carlson's Raiders.1942
Quinella1942
Go fly a kite1942
Stake out 1942
Acronym1943
Labonza1943
Pizzeria1943
Eager beaver1943
Hubba-hubba1944
Latchkey child1944
CustodianTo refer to a janitor. 1944
Hotrod1945
Expressway1945
Wolf-whistle1945
RackTo refer to an animal's antlers. 1945
Having a ball1945
Downscale As a verb; adjective appears in 1966. 1945
Hassle Noun. Verb is also American, appearing in 1951. 1945
CockamamieRumors of this existing as children's slang in the 1920s have not been confirmed. 1946
LatinoA shortening of Latinoamericano.1946
Drag race1947
Honcho1947
Show-and-tell1948
BitShort for 'binary digit'1948
CronyismTo refer to political favoritism; previous to his, it referred to friendship. 1950s
Big kahunaLater popularized in surfer slang in 1962.1950s
Cowabunga1950s
BitchingTo mean 'cool'.1950s
RentalTo refer to something that is for rent; previously it referred to what we today would refer to as 'rent'.1952
SlammerTo mean prison. 1952
Automated1952
HippieOriginally someone who was fashion conscious, changed to current meaning by 1965. 1953
Countdown1953
Wonk An effeminate man; by 1962 has changed to mean an overly-studious person. 1954
Urban renewal1955
Pass-fail1955
Byte1956
Gofer1956
Liftoff1956
Lead balloon1957
ShadesTo refer to sunglasses. 1958
Aerospace1958
FlakyTo mean 'eccentric'. Baseball slang. 1959
Kooky1959
Limo1959
Nuke1959
SpandexBrand name. 1959
Doofus1960s
Frag1960s
Bong1960s
Kook 1960
Upchuck1960
Barf1960
Pre-law1961
Boffo1961
Nitty-gritty1961
Wipeout1962
Chinese fire-drill1962
Kludge1962
DiscoShort for discotheque; first used for the style of music in 1972. 1964
Humongous1972
Repo1972
Lib1969
IntoMeaning to be strongly interested in something.1969
ScamCarnival slang. 1963
JimmiesFor ice cream sprinkles. 1963
JockFrom 'jockstrap'.1963
Whistleblower1963
Grunge and GrungySloppiness. The music and fashion style did not appear until the 1990s, but are also American, originating in Seattle.1965
Spaced-out1965
Boob tube1965
Skanky1965
Off the wall1966
Wise-ass1966
Zit1966
Credibility gap1966
Rip off1967
Honky1967
NarcShort for 'narcotics agent'.1967
TokeTo mean a puff of marijuana. 1968
Neato 1968
Biker'Motorcycle rider'1968
Choad1968
Aerobics1968
Dweeb1968
Low-profileTo refer to keeping something out of the public eye. The earlier use, referring to car tires, was also an Americanism, and appeared in 1957. 1970
Granola1970
Studly1971
Chairperson1971
Superfly1971
Gonzo1971
Ditzy1973
Buzz-cut1973
Gas-guzzler1973
EbonicsFrom 'ebony' + 'phonics'.1975
No-name1978
RapTo refer to the musical style.1979
Homeslice 1980s
Booyah1980s
High-fiveAs a noun, 1981 as a verb. 1980
NIMBY 1980
MeltThe sandwich. 1980
Waitstaff1981
WannabeSurfer slang1981
TubularTo mean 'cool'.1982
InterstateTo refer to a highway.1986
HoodShort for neighborhood. 1987
Neocon1987
Loogie1990
Percocet1991
Dudette1991
Brownfield1992
Ho1993
Cromulent1996

In addition to these, there are words that have been part of the English language for centuries, but started to fade out in England, only to be retained in America. Because of this, words such as 'mad' (to mean angry), 'overly', 'progress' (as a verb), 'kinfolk', 'sidewalk', 'notice' (as a verb), 'ass', 'sled', 'tardy', and 'reliable' may be said to be Americanisms. Other words are insufficiently documented to determine exactly when they started -- for example, 'hi' as a synonym for 'hello' is surely an Americanism, but it is not clearly documented when it moved from being a sound you yelled out to get attention to a simple greeting.

There are literally hundreds of Americanisms left of off this list. If I have forgotten your favorite, let me know and I will consider adding it.

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