Online Etymology Dictionary

attent (adj.): late 15c., "attentive," from Latin attentus, past participle of attendere (see attend). As a noun, "intention, aim" (early 13c.), from Old French atente "act of attending," from fem. of Latin attentus.
attention (n.): late 14c., "giving heed," from Latin attentionem (nominative attentio) "attention, attentiveness," noun of action from past participle stem of attendere "mental heeding" (see attend). Used with a remarkable diversity of verbs (e.g. pay, gather, attract, draw, call). As a military cautionary word preparative to giving a command, it is attested from 1792.
attention deficit disorder (n.): (abbreviated ADD) became a diagnosis in the third edition of the "Diagnostic and Statistical Manual of Mental Disorders" (1980); expanded to attention deficit hyperactivity disorder ("the co-existence of attentional problems and hyperactivity, with each behavior occurring infrequently alone;" ADHD) in DSM-III (1987).
attentive (adj.): late 14c. (implied in attentively), from Old French attentif, from Vulgar Latin *attenditus, from Latin attentus "heedful, observant" (see attend). Sense of "actively ministering to the needs and wants" (of another person) is from early 16c. Related: Attentively.
attentiveness (n.): mid-15c., from attentive + -ness.
attenuate (v.): "to make thin, to make less," 1520s, from Latin attenuatus "enfeebled, weak," past participle of attenuare "to make thin, lessen, diminish," from ad- "to" (see ad-) + tenuare "make thin," from tenuis "thin" (see tenet). Related: Attenuated; attenuating. Earlier was Middle English attenuen "to make thin (in consistency)," early 15c.
attenuation (n.): early 15c., of persons, "emaciation;" of diet, "reduction," from Latin attenuationem (nominative attenuatio) "a lessening," noun of action from past participle stem of attenuare (see attenuate).
attercop (n.): "spider," Old English attorcoppe, literally "poison-head," from ator "poison, venom," from Proto-Germanic *aitra- "poisonous ulcer" (cf. Old Norse eitr, Old High German eitar "poison;" German eiter "pus," Old High German eiz "abscess, boil;" Old English atorcræft "art of poisoning") + copp "top, summit, round head," probably also "spider" (cf. cobweb and Dutch spinne-cop "spider").
Amptes & attircoppes & suche oþer þat ben euere bisy ben maide to schewe man ensaumple of stodye & labour. [Elucidarium of Honorius of Autun (Wycliffite version) c.1400]
attest (v.): 1590s, from Middle French attester (Old French atester, 13c.) "affirm, attest," from Latin attestari "confirm," literally "bear witness to," from ad- "to" (see ad-) + testari "bear witness," from testis "witness" (see testament). Related: Attested; attesting.
attestation (n.): mid-15c., from Middle French attestation and directly from Latin attestationem (nominative attestatio) "an attesting, testimony," noun of action from past participle stem of attestari "to prove, confirm" (see attest).
Attic (adj.): 1590s, "pertaining to Attica," from Latin Atticus, from Greek Attikos "Athenian, of Attica," the region around Athens (see Attica). Attested from 1560s as an architectural term for a type of column base.
attic (n.): "top story under the roof of a house," 1855, shortened from attic storey (1724). The term Attic order in classical architecture meant a small, square decorative column of the type often used in a low story above a building's main facade, a feature associated with the region around Athens (see Attic). The word then was applied to "a low decorative facade above the main story of a building" (1690s in English), and it came to mean the space enclosed by such a structure. The modern use is via French. attique. "An attic is upright, a garret is in a sloping roof" [Weekley].
Attica: traditionally explained as from Greek Attikos (Latin Atticus) "of Athens" (see Athens); but perhaps ultimately from Greek akte "shore, maritime place," also "raised place."
attire (v.): c.1300, "to fit out, equip; to dress in finery, to adorn," from Old French atirier "to equip, ready, prepare," from a- "to" + tire "order, row, dress" (see tier). Related: Attired; attiring.
attire (n.): c.1300, "equipment of a man-at-arms; fine apparel," from attire (v.).
attitude (n.): 1660s, via French attitude (17c.), from Italian attitudine "disposition, posture," also "aptness, promptitude," from Late Latin aptitudinem (nominative aptitudo; see aptitude). Originally 17c. a technical term in art for the posture of a figure in a statue or painting; later generalized to "a posture of the body supposed to imply some mental state" (1725). Sense of "settled behavior reflecting feeling or opinion" is first recorded 1837. Connotations of "antagonistic and uncooperative" developed by 1962 in slang.
attitudinal (adj.): 1831, from Italian attitudine (see attitude) + -al (1).
attitudinize (v.): 1784, from attitudinal + -ize. Related: Attitudinized; attitudinizing.
atto-: word-forming element meaning "one quintillionth," 1962, from Danish atten "eighteen" (a quintillion is 10 to the 18th power), related to Old English eahtatene (see eighteen).
attorn (v.): late 13c., Anglo-French, "to turn over to another," from Old French atorner "to turn, turn to, assign, attribute, dispose," from a- "to" + tourner "to turn" (see turn (v.)). In feudal law, "to transfer homage or allegiance to another lord."
attorney (n.): early 14c. (mid-13c. in Anglo-Latin), from Old French atorné "(one) appointed," past participle of aturner "to decree, assign, appoint," from atorner (see attorn). The legal Latin form attornare influenced the spelling in Anglo-French. The sense is of "one appointed to represent another's interests."

In English law, a private attorney was one appointed to act for another in business or legal affairs (usually for pay); an attorney at law or public attorney was a qualified legal agent in the courts of Common Law who prepared the cases for a barrister, who pleaded them (the equivalent of a solicitor in Chancery). So much a term of contempt in England that it was abolished by the Judicature Act of 1873 and merged with solicitor.
Johnson observed that "he did not care to speak ill of any man behind his back, but he believed the gentleman was an attorney." [Boswell]
The double -t- is a mistaken 15c. attempt to restore a non-existent Latin original. Attorney general first recorded 1530s in sense of "legal officer of the state" (late 13c. in Anglo-French), from French, hence the odd plural (subject first, adjective second).
attract (v.): early 15c., from Latin attractus, past participle of attrahere "to draw, pull; to attract," from ad- "to" (see ad-) + trahere "draw" (see tract (n.1)).

Originally a medical term for the body's tendency to absorb fluids, nourishment, etc., or for a poultice treatment to "draw out" diseased matter (1560s). Of the ability of people or animals to draw others to them, it is attested from 1560s; of physical forces (magnetism, etc.), from c.1600 (implied in attraction). Related: Attracted; attracting.
attraction (n.): late 14c., from French attraction, from Latin attractionem (nominative attractio) "a drawing together," noun of action from past participle stem of attrahere (see attract). Originally a medical word, "absorption by the body;" meaning "action of drawing to" is from 1540s (again medical); extended to magnetic, then figuratively to personal (c.1600) qualities. Meaning "a thing which draws a crowd, interesting or amusing exhibition" is from 1829, a sense that developed in English and soon transferred to the French equivalent of the word.
attractive (adj.): late 14c., "absorptive," from Middle French attractif (14c.), from attract-, past participle stem of attrahere (see attract). Meaning "having the quality of drawing people's eye or interest" is from 1580s; sense of "pleasing, alluring" is from c.1600. Related: Attractively; attractiveness.
attrahent (n.): "that which attracts," 1660s, from Latin attrahentem (nominative attrahens), present participle of attrahere (see attract).
attributable (adj.): 1660s, from attribute (v.) + -able.
attribute (v.): late 14c., "assign, bestow," from Latin attributus, past participle of attribuere "assign to, add, bestow;" figuratively "to attribute, ascribe, impute," from ad- "to" + tribuere "assign, give, bestow" (see tribute). Related: Attributed; attributing.
attribute (n.): "quality ascribed to someone," late 14c., from Latin attributum "anything attributed," noun use of neuter of attributus (see attribute (v.)). Distinguished from the verb by pronunciation.
attributes (n.): "qualities belonging to someone or something," c.1600; see attribute (n.).
attribution (n.): late 15c., "action of bestowing or assigning," from Middle French attribution (14c.), from Latin attributionem (nominative attributio) "an assignment, attribution," noun of action from past participle stem of attribuere (see attribute). Meaning "thing attributed" is recorded from 1580s.
attributive (adj.): c.1600, from French attributif, from stem of Latin attributus (see attribute (v.)). As a noun, in grammar, from 1750. Related: Attributively; attributiveness.
attrit (v.): 1956, U.S. Air Force back-formation from attrition which attained currency during the Vietnam War. (A 17c. attempt at a verb produced attrite). Related: Attrited; attriting.
attrite (adj.): "worn down," 1620s, from Latin attritus, past participle of atterere (see attrition).
attrition (n.): 1540s, "abrasion, a scraping," from Latin attritionem (nominative attritio), literally "a rubbing against," noun of action from past participle stem of atterere "to wear, rub away," figuratively "to destroy, waste," from ad- "to" (see ad-) + terere "to rub" (see throw (v.)). The earliest sense in English is from Scholastic theology (late 14c.), "sorrow for sin merely out of fear of punishment," a minor irritation, and thus less than contrition. The sense of "wearing down of military strength" is a World War I coinage (1914). Figurative use by 1930.
attune (v.): 1590s, from tune (v.), "probably suggested by ATONE" [OED]. Related: Attuned; attuning.
attunement (n.): "a bringing into harmony," 1820, from attune + -ment.
ATV (n.): acronym of all-terrain vehicle, 1969.
atween (adv.): c.1400, from a- (1) + tween.
atwitter (adv.): 1833, from a- (1) + twitter.
atypical (adj.): 1847, from a- (2) "not" + typical. Related: Atypically.
Au: chemical symbol for "gold," from Latin aurum "gold" (see aureate).
au: French, "at the, to the," from Old French al, contraction of a le, with -l- softened to -u-, as also poudre from pulverem, chaud from calidus, etc. Used in many expressions in cookery, etc., which have crossed the Channel since 18c., e.g. au contraire, literally "on the contrary;" au gratin, literally "with scrapings;" au jus, literally "with the juice."
au courant (adj.): "aware of current events," 1762, French, literally "with the current" (see current (n.)).
au fait (adj.): 1743, French, "to the point, to the matter under discussion," literally "to the fact," from fait "fact" (see feat). Used in French with sense of "acquainted with the facts."
au naturel (adj.): 1817, French, literally "in the natural state;" originally meaning "uncooked," but used euphemistically for "undressed." See natural (adj.).
au pair (n.): 1897 of the arrangement, 1960 of the girl; French, literally "on an equal footing" (see pair (n.)).
au revoir: 1690s, French, literally "to the seeing again."
aubade (n.): "musical announcement of dawn," from French aubade (15c.), from Provençal aubada, from auba "dawn," from Latin alba, fem. of albus "white" (see alb).
aubain (n.): 1727, from French aubaine (12c.), of unknown origin, perhaps from Medieval Latin Albanus, but the sense is obscure. Klein suggests Frankish *alibanus, literally "belonging to another ban." A right of French kings, whereby they claimed the property of every non-naturalized stranger who died in their realm. Abolished 1819.
aubergine (n.): "eggplant," 1794, from French aubergine, "fruit of the eggplant" (Solanum esculentum), diminutive of auberge "a kind of peach," variant of alberge, from Spanish alberchigo "apricot" [OED]. Klein derives the French word from Catalan alberginera, from Arabic al-badinjan "the eggplant," from Persian badin-gan, from Sanskrit vatin-ganah. As a color like that of the eggplant fruit, it is attested from 1895.