Online Etymology Dictionary

aero-: word-forming element meaning "air, atmosphere; aircraft; gases," from Greek aero-, comb. form of aer (genitive aeros) "air, lower atmosphere" (see air (n.1)).
aerobatics (n.): aircraft tricks, "trick flying," 1914, from aero- + ending from acrobat (also see -ics). Earlier (1879) it meant "the art of constructing and using airships; aerial navigation; aeronautics."
aerobic (adj.): "living only in the presence of oxygen," 1875, (after French aérobie, coined 1863 by Louis Pasteur) from Greek aero- "air" (see aero-) + bios "life" (see bio-).
aerobics (n.): method of exercise and a fad in early 1980s, American English, coined 1968 by Kenneth H. Cooper, U.S. physician, from aerobic (also see -ics) on the notion of activities which require modest oxygen intake and thus can be maintained.
aerodonetics (n.): science of gliding, 1907, from Greek aero- "air" (see aero-) + stem of donein "to shake, drive about." Also see -ics.
aerodrome (n.): 1902, from aero- on analogy of hippodrome. Earlier (1891) a name for a flying machine.
aerodynamic (adj.): also aero-dynamic, 1847; see aero- + dynamic (adj.). Compare German aerodynamische (1835), French aérodynamique.
aerodynamics (n.): 1837, from aero- "air" + dynamics.
aerofoil (n.): 1907, from aero- + foil (n.).
aeronautics (n.): 1824, from aeronautic (1784), from French aéronautique, from aéro- (see aero-) + nautique "of ships," from Latin nauticus, from Greek nautikos (see nautical). Originally of balloons. Also see -ics. Aeronaut "balloonist" is from 1784.
aerophyte (n.): 1840, perhaps via French aerophyte, from aero- + -phyte "plant."
aeroplane (n.): 1866, from French aéroplane (1855), from Greek aero- "air" (see air (n.1)) + stem of French planer "to soar," from Latin planus "level, flat" (see plane (n.1)). Originally in reference to surfaces (such as the protective shell casings of beetles' wings); meaning "heavier than air flying machine" first attested 1873, probably an independent English coinage (see airplane).
aerosol (n.): 1919, from aero- "air" + first syllable in solution. A term in physics; modern commercial application is from 1940s.
aerospace (adj.): 1958, American English, from aero- "atmosphere" + (outer) space (n.).
Aeschylus: Greek Aiskhylos (525-456 B.C.E.), Athenian soldier, poet, and playwright, Father of Tragedy.
Aesir (n.): chief gods of Scandinavian religion, from Old Norse plural of ass "god," from Proto-Germanic *ansu- (source also of Old High German ansi, Old English os, Gothic ans "god"), from PIE *ansu- "spirit" (source also of first element in Avestan Ahura Mazda).
Aesop: Greek Aisopos, semi-legendary 6c. B.C.E. fablist.
Aesopic (adj.): 1927, in the context of Soviet literary censorship, in reference to writing "obscure or ambiguous, often allegorical, which disguises dissent," from Aesop, the traditional father of the allegorical fable, + -ic. The term (Russian ezopovskii, 1875) arose under the Tsars. The style was used by Russian communists, who, once they took power, used the word in charges against their own dissidents.
aesthete (n.): attested from 1878, in vogue 1881, from Greek aisthetes "one who perceives," from stem of aisthanesthai "to perceive, to feel" (see aesthetic). Or perhaps from aesthetic on the model of athlete/athletic.
1. Properly, one who cultivates the sense of the beautiful; one in whom the artistic sense or faculty is highly developed; one very sensible of the beauties of nature or art.--2. Commonly, a person who affects great love of art, music, poetry, and the like, and corresponding indifference to practical matters; one who carries the cultivation of subordinate forms of the beautiful to an exaggerated extent: used in slight contempt. [Century Dictionary, 1897]

I want to be an aesthete,
And with the aesthetes stand;
A sunflower on my forehead,
And a lily in my hand.

["Puck," Oct. 5, 1881]
aesthetic (n.): 1798, from German Ästhetisch or French esthétique, both from Greek aisthetikos "sensitive, perceptive," from aisthanesthai "to perceive (by the senses or by the mind), to feel," from PIE *awis-dh-yo-, from root *au- "to perceive" (see audience).

Popularized in English by translations of works of Immanuel Kant and used originally in the classically correct sense "the science which treats of the conditions of sensuous perception." Kant had tried to correct the term after Alexander Baumgarten had taken it in German to mean "criticism of taste" (1750s), but Baumgarten's sense attained popularity in English c. 1830s (despite scholarly resistance) and removed the word from any philosophical base. Walter Pater used it (1868) to describe the late 19c. movement that advocated "art for art's sake," which further blurred the sense. As an adjective by 1803. Related: Aesthetically.
aestheticism (n.): 1855, from aesthetic + -ism.
aesthetics (n.): 1803, from aesthetic (also see -ics).
aet.: "aged (some number of years)," abbreviation of Latin aetatis "of the age of," genitive singular of aetas "age" (see age (n.)).
aetio-: word-forming element used in chemistry and indicating "a fundamental degradation product of a complex organic compound" [Flood], from Latinized comb. form of Greek aitia "a cause, an origin" (see etiology).
afanc (n.): cattle-devouring aquatic monster in Celtic countries, from Celtic *abankos "water-creature," from *ab- "water" (source also of Welsh afon, Breton aven "river," Latin amnis "stream, river," which is believed to be of Italo-Celtic origin), from PIE root *ap- (2) "water" (for which see water (n.1)).
afar (adv.): contraction of Middle English of feor (late 12c.), on ferr (c. 1300), from Old English feor "far" (see far); the a- (1) in compounds representing both of and on (which in this use meant the same thing). Spelled afer in 14c.
afeared (adj.): Old English afæred, past participle of now-obsolete afear (Old English afæran) "to terrify," from a- (1) + færan (see fear (v.)). Used frequently by Shakespeare, but supplanted in literary English after 1700 by afraid (q.v.). It still survives in popular and colloquial speech.
affability (n.): late 15c., from Old French affabilité (14c.), noun of quality from affable (see affable).
affable (adj.): late 15c., from Old French afable (14c.), from Latin affabilis "approachable, courteous, kind, friendly," literally "who can be (easily) spoken to," from affari "to speak to," from ad- "to" (see ad-) + fari "to speak," from PIE root *bha- (2) "to speak, tell, say" (see fame (n.)). Related: Affably.
affair (n.): c. 1300, "what one has to do," from Anglo-French afere, Old French afaire "business, event; rank, estate" (12c., Modern French affaire), from the infinitive phrase à faire "to do," from Latin ad "to" (see ad-) + facere "to do, make" (see factitious).

A Northern word originally, brought into general use and given a French spelling by Caxton (15c.). General sense of "vague proceedings" (in romance, war, etc.) first attested 1702. Meaning "an affair of the heart; a passionate episode" is from French affaire de coeur (itself attested in English from 1809); to have an affair with someone in this sense is by 1726, earlier have an affair of love:
'Tis manifeſtly contrary to the Law of Nature, that one Woman ſhould cohabit or have an Affair of Love with more than one Man at the ſame time. ["Pufendorf's Law of Nature and Nations," transl. J. Spavan, London, 1716]

Thus, in our dialect, a vicious man is a man of pleasure, a sharper is one that plays the whole game, a lady is said to have an affair, a gentleman to be a gallant, a rogue in business to be one that knows the world. By this means, we have no such things as sots, debauchees, whores, rogues, or the like, in the beau monde, who may enjoy their vices without incurring disagreeable appellations. [George Berkeley, "Alciphron or the Minute Philosopher," 1732]
affairs (n.): "ordinary business," late 15c., plural of affair (n.).
affect (n.): late 14c., "mental state," from Latin noun use of affectus "furnished, supplied, endowed," figuratively "disposed, constituted, inclined," past participle of afficere "to do; treat, use, manage, handle; act on; have influence on, do something to," a verb of broad meaning, from ad- "to" (see ad-) + facere (past participle factus) "to make, do" (see factitious). Perhaps obsolete except in psychology. Related: Affects.
affect (v.2): "to make a pretense of," 1660s, earlier "to assume the character of (someone)," 1590s; originally in English "to aim at, aspire to, desire" (early 15c.), from Middle French affecter (15c.), from Latin affectare "to strive after, aim at," frequentative of afficere (past participle affectus) "to do something to, act on" (see affect (n.)). Related: Affected; affecting.
affect (v.1): "to make an impression on," 1630s; earlier "to attack" (c. 1600), "act upon, infect" (early 15c.), from affect (n.). Related: Affected; affecting.
affectation (n.): "studied display," 1540s, from French affectation (16c.) or directly from Latin affectationem (nominative affectatio) "a striving after, a claiming," noun of action from past participle stem of affectare "to strive for" (see affect (v.2)).
affected (adj.): past participle adjective from affect (v.2); 1530s in the now-obsolete sense "favorably disposed" (preserved in disaffected); meaning "artificially displayed" is recorded from 1580s.
affection (n.): early 13c., "an emotion of the mind, passion, lust as opposed to reason," from Old French afection (12c.) "emotion, inclination, disposition; love, attraction, enthusiasm," from Latin affectionem (nominative affectio) "a relation, disposition; a temporary state; a frame, constitution," noun of state from past participle stem of afficere "to do something to, act on" (see affect (n.)). Sense developed from "disposition" to "good disposition toward" (late 14c.). Related: Affections.
affectionate (adj.): 1580s, "fond, loving," from affection + -ate (1). Early, now mostly obsolete, senses included "inclined" (1530s), "prejudiced" (1530s), "passionate" (1540s), "earnest" (c. 1600). Other forms also used in the main modern sense of the word included affectious (1580s), affectuous (mid-15c.).
affectionately (adv.): 1580s, from affectionate + -ly (2).
affiance (v.): 1520s, "to promise," from Old French afiancier "to pledge, promise, give one's word," from afiance (n.) "confidence, trust," from afier "to trust," from Late Latin affidare, from ad- "to" (see ad-) + fidare "to trust," from fidus "faithful" from the same root as fides "faith" (see faith). From mid-16c. especially "to promise in marriage." Related: Affianced; affiancing.
affidavit (n.): 1590s, from Medieval Latin affidavit, literally "he has stated on oath," third person singular perfective of affidare "to trust," from Latin ad- "to" (see ad-) + fidare "to trust," from fidus "faithful," from the same root as fides "faith" (see faith). So called from being the first word of sworn statements.
affiliate (v.): 1761, from Latin affiliatus, past participle of affiliare "to adopt" (see affiliation). Outside legal use, always figurative. Related: Affiliated; affiliating.
affiliate (adj.): 1858, from affiliate (v.).
affiliate (n.): 1846, from affiliate (v.).
affiliation (n.): 1751, "adoption," from French affiliation, from Medieval Latin affiliationem (nominative affiliatio), noun of action from past participle stem of Latin affiliare "to adopt a son," from ad- "to" (see ad-) + filius "son" (see filial). Figurative sense of "adoption by a society, of branches" first recorded 1799 (the verb affiliate in this sense is from 1761).
affinity (n.): c. 1300, "relation by marriage" (as opposed to consanguinity), from Old French afinité (12c.), from Latin affinitatem (nominative affinitas) "neighborhood, relationship by marriage," noun of state from affinis "adjacent," also "kin by marriage," literally "bordering on," from ad- "to" (see ad-) + finis "a border, a boundary" (see finish (v.)). Used figuratively since c. 1600 of structural relationships in chemistry, philology, etc. Meaning "natural attraction" (as though by family) is from 1610s.
affirm (v.): c. 1300, from Old French afermier (Modern French affirmer) "affirm, confirm; strengthen, consolidate," from Latin affirmare "to make steady, strengthen," figuratively "confirm, corroborate," from ad- "to" (see ad-) + firmare "strengthen, make firm," from firmus "strong" (see firm (adj.)). Spelling refashioned 16c. in French and English on Latin model. Related: Affirmed; affirming.
affirmation (n.): early 15c., "assertion that something is true," from Old French afermacion (14c.), from Latin affirmationem (nominative affirmatio) "an affirmation, solid assurance," noun of action from past participle stem of affirmare (see affirm). In law, as the Quaker alternative to oath-taking, it is attested from 1690s.
affirmative (adj.): "answering 'yes,'" mid-15c., from use in logic; from Middle French affirmatif (13c.), from Latin affirmativus, from affirmat-, past participle stem of affirmare (see affirm). As a noun from early 15c. Affirmative action "positive or corrective effort by employers to prevent discrimination in hiring or promotion" is attested from 1935 with regard to labor unions; specific racial sense is from 1961; now often used in reference to hiring quotas, etc.
affirmatively (adv.): mid-15c., from affirmative + -ly (2).