Online Etymology Dictionary

antivirus (n.): 1903, from anti- + virus.
antler (n.): late 14c., from Anglo-French auntiler, Old French antoillier (14c., Modern French andouiller) "antler," perhaps from Gallo-Roman cornu *antoculare "horn in front of the eyes," from Latin ante "before" (see ante) + ocularis "of the eyes" (see ocular). This etymology is doubted by some because no similar word exists in any other Romance language, but compare German Augensprossen "antlers," literally "eye-sprouts," for a similar formation.
Antonia: fem. proper name, from Latin Antonia, fem. of Antonius (see Anthony).
Antonine (adj.): 1680s, in reference to Roman emperors Antoninus Pius (ruled 138-161 C.E.) and Marcus Aurelius Antoninus (161-180).
antonomasia (n.): use of an epithet for a proper name (or vice versa; as in His Holiness for the name of a pope), 1580s, from Latin, from Greek antonomasia, from antonomazein "to name instead, call by a new name," from anti "instead" (see anti-) + onomazein "to name," from onoma "name" (see name (n.)).
Antony: masc. proper name, from Latin Antonius, name of a Roman gens (see Anthony).
antonym (n.): 1867, coined to serve as opposite of synonym, from Greek anti- "equal to, instead of, opposite" (see anti-) + -onym "name" (see name (n.)). Perhaps introduced to English in the book "Synonyms and Antonyms" (1867) by the Ven. C.J. Smith, M.A.
UNDER the head of Synonyms and Antonyms, Archdeacon Smith arranges words which form an antithesis to one another. The word "antonym" is, we believe, a new formation but useful. ["Journal of Sacred Literature," July 1867]
French antonyme (1842), German antonym (by 1859) are older. The un-Greek alternative counterterm has been left to fade.
antrum (n.): "a cave or cavity," late 14c., medical Latin, from Greek antron "cave."
antsy (adj.): 1838, American English, from plural of ant + -y (2); probably reflecting the same image as the slang expression have ants in (one's) pants "be restless and fidgety" from a century later. Related: Antsiness.
Antwerp: port city in Belgium, French Anvers, from a Germanic compound of *anda "at" + *werpum "wharf" (see wharf). Folk etymology connects the first word with hand.
Anubis: jackal-headed god of Egyptian religion, from Greek Anoubis, from Egyptian Anpu.
anuria (n.): 1838, medical Latin, from Greek an-, privative prefix (see an- (1)), + ouron "urine" (see urine) + abstract noun ending -ia.
anus (n.): "inferior opening of the alimentary canal," 1650s, from Old French anus, from Latin anus "ring, anus," from PIE root *ano- "ring." So called for its shape; compare Greek daktylios "anus," literally "ring (for the finger)," from daktylos "finger."
anvil (n.): Old English anfilt, a Proto-Germanic compound (cognates: Middle Dutch anvilt, Old High German anafalz, Dutch aanbeeld, Danish ambolt "anvil") from *ana- "on" + *filtan "hit" (see felt (n.)). The ear bone so called from 1680s. Anvil Chorus is based on the "Gypsy Song" that opens Act II of Giuseppe Verdi's opera "Il Trovatore," first performed in Teatro Apollo, Rome, Jan. 19, 1853.
anxiety (n.): 1520s, from Latin anxietatem (nominative anxietas) "anguish, anxiety, solicitude," noun of quality from anxius (see anxious). Psychiatric use dates to 1904. Age of Anxiety is from Auden's poem (1947). For "anxiety, distress," Old English had angsumnes, Middle English anxumnesse.
anxious (adj.): 1620s, from Latin anxius "solicitous, uneasy, troubled in mind" (also "causing anxiety, troublesome"), from angere, anguere "choke, squeeze," figuratively "torment, cause distress" (see anger (v.)). The same image is in Serbo-Croatian tjeskoba "anxiety," literally "tightness, narrowness." Related: Anxiously; anxiousness.
any (adj.): Old English ænig "any, anyone," literally "one-y," from Proto-Germanic *ainagas (source also of Old Saxon enig, Old Norse einigr, Old Frisian enich, Dutch enig, German einig), from PIE *oi-no- "one, unique" (see one). The -y may have diminutive force here.

Emphatic form any old ______ (British variant: any bloody ______) is recorded from 1896. At any rate is recorded from 1847. Among the large family of compounds beginning with any-, anykyn "any kind" (c. 1300) did not survive, and Anywhen (1831) is rarely used, but OED calls it "common in Southern [British] dialects."
anybody (n.): c. 1300, ani-bodi, from any + body. One-word form is attested by 1826. Phrase anybody's game (or race, etc.) is from 1840.
anyhow (adv.): 1740, from any + how (adv.). Unlike the cases of most other any + (interrogative) compounds, there is no record of it in Old or Middle English. Emphatic form any old how is recorded from 1900, American English.
anymore (adv.): one-word form by 1865, from any + more.
anyone (n.): Old English, two words, from any + one. Old English also used ænigmon in this sense. One-word form from 1844.
anyplace (n.): 1911, from any + place.
anything (n.): late Old English aniþing, from any + thing. But Old English ænig þinga apparently also meant "somehow, anyhow" (glossing Latin quoquo modo).
anythingarian (n.): "one indifferent to religious creeds," c. 1704, originally dismissive, from anything on model of trinitarian, unitarian, etc.
anytime (adv.): one-word form by 1854, from any + time (n.).
anyway (adv.): 1560s, any way "in any manner;" variant any ways (with adverbial genitive) attested from c. 1560, prepositional phrase by any way is from late 14c.; see any + way (n.). One-word form predominated from 1830s. As an adverbial conjunction, from 1859. Middle English in this sense had ani-gates "in any way, somehow" (c. 1400).
anyways (adv.): see anyway.
anywhere (adv.): late 14c., from any + where. Earlier words in this sense were owhere, oughwhere, aywhere, literally "aught where" (see aught (1)).
anywise (adv.): Old English ænige wisan, from any + wise (n.). One-word form from c. 1200.
Anzac: 1915, acronym of Australian and New Zealand Army Corps. First used in reference to the Gallipoli campaign.
AOL: dominant online service of the late 1990s, initialism (acronym) of America Online, company name from late 1989.
aorist (n.): 1580s, the simple past tense of Greek verbs, from Greek aoristos (khronos) "indefinite (tense)," from privative prefix a- "not" (see a- (3)) + horistos "limited, defined," verbal adjective from horizein "to limit, define," from horos "boundary, limit, border" (see horizon).
aorta (n.): 1570s, from Medieval Latin aorta, from Greek aorte, term applied by Aristotle to the great artery of the heart, literally "what is hung up," from aeirein "to lift, heave, raise," which is of uncertain origin; related to the second element in meteor. Used earlier by Hippocrates of the bronchial tubes. Related: Aortal; aortic.
AP: abbreviation of Associated Press, first recorded 1879; the organization was founded May 1848 as co-operative news gathering effort among New York City newspaper publishers covering the war with Mexico.
ap- (2): patronymic prefix in Welsh names, earlier map "son," cognate with Gaelic mac. Since 17c. merged into surnames (Ap Rhys = Price, Ap Evan = Bevan, etc.).
It is said that a Welshman who evidently was not willing to be surpassed in length of pedigree, when making out his genealogical tree, wrote near the middle of his long array of 'aps' -- "about this time Adam was born." ["Origin and Significance of our Names," "The Chautauquan," Oct. 1887-July 1888]
ap- (1): form of Latin ad- before words beginning in -p-; see ad-.
apace (adv.): mid-14c., from a pace, literally "at a pace," but usually with a sense of "at a good pace," from a- (1) "on" + pace (n.).
Apache: 1745, from American Spanish (1598), probably from Yavapai (a Yuman language) 'epache "people." Sometimes derived from Zuni apachu "enemy" (see F.W. Hodge, "American Indians," 1907), but this seems to have been the Zuni name for the Navajo.

French journalistic sense of "Parisian gangster or thug" first attested 1902. Apache dance was the World War I-era equivalent of 1990s' brutal "slam dancing." Fenimore Cooper's Indian novels were enormously popular in Europe throughout the 19c., and comparisons of Cooper's fictional Indian ways in the wilderness and underworld life in European cities go back to Dumas' "Les Mohicans de Paris" (1854-1859). It is probably due to the imitations of Cooper (amounting almost to plagiarisms) by German author Karl May (1842-1912) that Apaches replaced Mohicans in popular imagination. Also compare Mohawk.
apanage (n.): see appanage.
apart (adv.): late 14c., from Old French à part "to the side," from Latin ad "to" (see ad-) + partem, accusative of pars "a side" (see part (n.)).
apartheid (n.): 1947 (policy begun 1948), from Afrikaans apartheid (1929 in a South African socio-political context), literally "separateness," from Dutch apart "separate" (from French àpart; see apart) + suffix -heid, cognate of English -hood. The official English synonym was separate development (1955).
"Segregation" is such an active word that it suggests someone is trying to segregate someone else. So the word "apartheid" was introduced. Now it has such a stench in the nostrils of the world, they are referring to "autogenous development." [Alan Paton, "New York Times," Oct. 24, 1960]
apartment (n.): 1640s, "private rooms for the use of one person within a house," from French appartement (16c.), from Italian appartimento, literally "a separated place," from appartere "to separate," from a "to" (see ad-) + parte "side, place," from Latin partem (see part (n.)). Sense of "set of private rooms in a building entirely of these" (the U.S. equivalent of British flat) is first attested 1874.
apathetic (adj.): 1744, from apathy + -ic, on model of pathetic.
apathy (n.): c. 1600, "freedom from suffering," from French apathie (16c.), from Latin apathia, from Greek apatheia "freedom from suffering, impassability, want of sensation," from apathes "without feeling, without suffering or having suffered," from a- "without" (see a- (3)) + pathos "emotion, feeling, suffering" (see pathos). Originally a positive quality; sense of "indolence of mind, indifference to what should excite" is from c. 1733.
APB: also a.p.b., 1960, police jargon initialism (acronym) for all-points bulletin, itself attested by 1953 (perhaps more in the jargon of detective novels than in actual police use).
ape (n.): Old English apa "ape, monkey," from Proto-Germanic *apan (source also of Old Saxon apo, Old Norse api, Dutch aap, German affe), perhaps borrowed in Proto-Germanic from Celtic (compare Old Irish apa) or Slavic (compare Old Bohemian op, Slovak opitza), perhaps ultimately from a non-Indo-European language.

Apes were noted in medieval times for mimicry of human action, hence, perhaps, the other figurative use of the word, to mean "a fool." To go ape (in emphatic form, go apeshit) "go crazy" is 1955, U.S. slang. To lead apes in hell (1570s) was the fancied fate of one who died an old maid.
ape (v.): "to imitate," 1630s, but the notion is implied earlier, as in the phrase play the ape (1570s), Middle English apeshipe "ape-like behavior, simulation" (mid-15c.); and the noun sense of "one who mimics" may date from early 13c. Related: Aped; aping.
ape-man (n.): hypothetical "missing link," 1879, in a translation of Haeckel, from ape (n.) + man (n.). Man-ape is attested from 1878. The name Martin Halfape appears in an English roll from 1227.
apercu (n.): "quick impression, sketch, brief survey," 1820s, from French aperçu (18c. in this sense), noun use of past participle of apercevoir "to perceive" (11c.), from Gallo-Roman *adpercipere, from Latin ad "to" (see ad-) + percipere "to perceive" (see perceive).
aperiodic (adj.): 1874, from a- (2), privative prefix, + periodic.