Online Etymology Dictionary

acupuncture (n.): 1680s, "pricking with a needle" to ease pain, from Latin acus "needle" (see acuity) + puncture. The verb is first recorded 1972.
acupuncturist (n.): 1843, from acupuncture + -ist.
acute (adj.): late 14c., originally of fevers and diseases, "coming and going quickly" (opposed to a chronic), from Latin acutus "sharp, pointed," figuratively "shrill, penetrating; intelligent, cunning," past participle of acuere "sharpen" (see acuity). Meaning "sharp, irritating" is from early 15c. Meaning "intense" is from 1727. Related: Acutely; acuteness.
ad (n.): 1841, shortened form of advertisement. Long resisted by those in the trade, and according to Mencken (1945) denounced by William C. D'Arcy (president of Associated Advertising Clubs of the World) as "the language of bootblacks, ... beneath the dignity of men of the advertising profession."
ad hoc: Latin, literally "for this (specific purpose)."
ad hominem: c. 1600, Latin, literally "to a man," from ad "to" (see ad-) + hominem, accusative of homo "man" (see homunculus).
ad infinitum: "endlessly," Latin, literally "to infinity" from ad "to" (see ad-) + infinitum "infinity," neuter of adjective infinitus "endless" (see infinite). English version to infinity is attested from 1630s.
ad lib: 1811, shortened from Latin ad libitum "at one's pleasure, as much as one likes" (c. 1600), from ad "to" (see ad-) + libitum, accusative of libere "to please" (see libido). First recorded as one word 1919 (v.), 1925 (n.).
ad nauseam: "to a sickening extent," Latin, literally "to sickness," from ad "to" (see ad-) + nauseam, accusative of nausea (see nausea).
ad valorem: type of customs duties, 1711, Modern Latin, "(in proportion) to the value," from ad "to" (see ad-) + Late Latin valorem, accusative of valor "value" (see value (n.)).
ad-: word-forming element expressing direction toward or in addition to, from Latin ad "to, toward" in space or time; "with regard to, in relation to," as a prefix, sometimes merely emphatic, from PIE *ad- "to, near, at" (cognate with Old English æt; see at). Simplified to a- before sc-, sp- and st-; modified to ac- before many consonants and then re-spelled af-, ag-, al-, etc., in conformity with the following consonant (as in affection, aggression). In Old French, reduced to a- in all cases (an evolution already underway in Merovingian Latin), but written forms in French were refashioned after Latin in 14c. and English did likewise 15c. in words it had picked up from Old French. In many cases pronunciation followed the shift.
Ada: fem. proper name, from Hebrew Adha, literally "ornament."
adage (n.): "brief, familiar proverb," 1540s, Middle French adage, from Latin adagium "adage, proverb," apparently from adagio, from ad- "to" (see ad-) + *agi-, root of aio "I say," from PIE *ag- "to speak." But Tucker thinks the second element is rather ago "set in motion, drive, urge."
adagio (adv.): c. 1746, in music, "slowly, leisurely and gracefully," Italian, from ad agio, from ad "to, at" (see ad-) + agio "leisure," from Vulgar Latin adiacens, present participle of adiacere "to lie at, to lie near" (compare adjacent). In noun sense of "a slow movement," first attested 1784.
Adam: masc. proper name, Biblical name of the first man, progenitor of the human race, from Hebrew adam "man," literally "(the one formed from the) ground" (Hebrew adamah "ground"); compare Latin homo "man," humanus "human," humus "earth, ground, soil." To not know (someone) from Adam "not know him at all" is first recorded 1784.
Adam's apple (n.): 1731, corresponding to Latin pomum Adami, perhaps an inexact translation of Hebrew tappuah haadam, literally "man's swelling," from ha-adam "the man" + tappuah "anything swollen." The reference is to the legend that a piece of the forbidden fruit (commonly believed to be an apple) that Eve gave Adam stuck in his throat. The term is mentioned in early 15c. as the name of an actual oriental and Mediterranean fruit, a variety of lime with an indentation fancied to resemble the marks of Adam's teeth.
adamant (adj.): late 14c., "hard, unbreakable," from adamant (n.). Figurative sense of "unshakeable" first recorded 1670s. Related: Adamantly; adamance.
adamant (n.): mid-14c., from Old French adamant and directly from Latin adamantem (nominative adamas) "adamant, hardest iron, steel," also figuratively, of character, from Greek adamas (genitive adamantos) "unbreakable, inflexible" metaphoric of anything unalterable, also the name of a hypothetical hardest material, perhaps literally "invincible," from a- "not" + daman "to conquer, to tame" (see tame (adj.)), or else a word of foreign origin altered to conform to Greek.

Applied in antiquity to a metal resembling gold (Plato), white sapphire, magnet (by Ovid, perhaps via confusion with Latin adamare "to love passionately"), steel, emery stone, and especially diamond (see diamond). "The name has thus always been of indefinite and fluctuating sense" [Century Dictionary]. The word was in Old English as aðamans "a very hard stone."
adamantine (adj.): c. 1200, from Latin adamantinus "hard as steel, inflexible," from Greek adamantinos, from adamas (see adamant (n.)).
Adamite (n.): "human being, descendant of Adam" the Biblical first man, 1630s, from Adam + -ite (1). Used from 1620s in reference to sects or groups that practice nudism, in reference to the state of Adam before the Fall.
adapt (v.): early 15c. (implied in adapted) "to fit (something, for some purpose)," from Middle French adapter (14c.), from Latin adaptare "adjust," from ad- "to" (see ad-) + aptare "to join," from aptus "fitted" (see apt). Meaning "to undergo modification so as to fit new circumstances" (intransitive) is from 1956. Related: Adapting.
adaptability (n.): 1660s, from adapt + -ability.
adaptable (adj.): 1800, from adapt + -able.
adaptation (n.): c. 1600, "action of adapting," from French adaptation, from Late Latin adaptationem (nominative adaptatio), noun of action from past participle stem of adaptare (see adapt). Meaning "condition of being adapted" is from 1670s. Sense of "modification of a thing to suit new conditions" is from 1790. Biological sense first recorded 1859 in Darwin's writings.
adapter (n.): 1801, agent noun from adapt. Electrical engineering sense from 1907.
add (v.): late 14c., "to join or unite (something to something else)," from Latin addere "add to, join, attach, place upon," from ad- "to" (see ad-) + -dere comb. form meaning "to put, place," from dare "to give" (see date (n.1)). Meaning "to do sums, do addition" also is from late 14c. Related: Added; adding. To add up "make sense" is from 1942.
add-on (n.): "additional component," 1941, from add (v.) + on.
added (adj.): "additional," c. 1600, past participle adjective from add (v.).
addendum (n.): 1794, literally "something added," from Latin addendum, neuter of addendus "that which is to be added," gerundive of addere (see add (v.)). Classical plural form is addenda.
adder (n.): Old English næddre "a snake, serpent, viper," from Proto-Germanic *nædro "a snake" (source also of Old Norse naðra, Middle Dutch nadre, Old High German natra, German Natter, Gothic nadrs), from PIE root *netr- (source also of Latin natrix "water snake," probably by folk-association with nare "to swim;" Old Irish nathir, Welsh neidr "adder").

The modern form represents a faulty separation 14c.-16c. into an adder, for which see also apron, auger, nickname, humble pie, umpire. Nedder is still a northern English dialect form. Folklore connection with deafness is via Psalm lviii:1-5. The adder is said to stop up its ears to avoid hearing the snake charmer called in to drive it away. Adderbolt (late 15c.) was a former name for "dragonfly."
addict (v.): 1530s (implied in addicted), from Latin addictus, past participle of addicere "to deliver, award, yield; give assent, make over, sell," figuratively "to devote, consecrate; sacrifice, sell out, betray" from ad- "to" (see ad-) + dicere "say, declare" (see diction), but also "adjudge, allot." Earlier in English as an adjective, "delivered, devoted" (1520s). Related: Addicted; addicting.
addict (n.): 1909, in reference to morphine, from addict (v.).
addicted (adj.): 1530s, "delivered over" by judicial sentence; past participle adjective from addict (v.). Modern sense of "dependent" is short for self-addicted "to give over or award (oneself) to someone or some practice" (1560s; exact phrase from c. 1600); specialization to narcotics dependency is from c. 1910.
addiction (n.): c. 1600, "tendency," of habits, pursuits, etc.; 1640s as "state of being self-addicted," from Latin addictionem (nominative addictio) "an awarding, a devoting," noun of action from past participle stem of addicere (see addict (v.)). Earliest sense was less severe: "inclination, penchant," but this has become obsolete. In main modern sense it is first attested 1906, in reference to opium (there is an isolated instance from 1779, with reference to tobacco).
addictive (adj.): 1815, a word in chemistry and medicine; 1939 in the narcotics sense, from addict (v.) + -ive. Related: Addictively; addictiveness.
addition (n.): late 14c., "action of adding numbers;" c. 1400, "that which is added," from Old French adition "increase, augmentation" (13c.), from Latin additionem (nominative additio) "an adding to, addition," noun of action from past participle stem of addere (see add). Phrase in addition to "also" is from 1680s.
additional (adj.): 1640s, from addition + -al (1). Related: Additionally.
additive (adj.): 1690s, "tending to be added," from Latin additivus "added, annexed," from past participle stem of addere (see addition).
additive (n.): "something that is added" to a chemical solution or food product, 1945, from additive (adj.).
addle (v.): 1712, from addle (n.) "urine, liquid filth," from Old English adela "mud, mire, liquid manure" (cognate with Old Swedish adel "urine," Middle Low German adel, Dutch aal "puddle").

Used in noun phrase addle egg (mid-13c.) "egg that does not hatch, rotten egg," literally "urine egg," a loan-translation of Latin ovum urinum, which is itself an erroneous loan-translation of Greek ourion oon "putrid egg," literally "wind egg," from ourios "of the wind" (confused by Roman writers with ourios "of urine," from ouron "urine"). Because of this usage, from c. 1600 the noun in English was taken as an adjective meaning "putrid," and thence given a figurative extension to "empty, vain, idle," also "confused, muddled, unsound" (1706). The verb followed a like course. Related: Addled; addling.
address (v.): early 14c., "to guide or direct," from Old French adrecier "go straight toward; straighten, set right; point, direct" (13c.), from Vulgar Latin *addirectiare "make straight," from Latin ad "to" (see ad-) + *directiare, from Latin directus "straight, direct" (see direct (v.)). Late 14c. as "to set in order, repair, correct." Meaning "to write as a destination on a written message" is from mid-15c. Meaning "to direct spoken words (to someone)" is from late 15c. Related: Addressed; addressing.
address (n.): 1530s, "dutiful or courteous approach," from address (v.) and from French adresse. Sense of "formal speech" is from 1751. Sense of "superscription of a letter" is from 1712 and led to the meaning "place of residence" (1888).
addressee (n.): 1810; see address (v.) + -ee.
adduce (v.): early 15c., from Latin adducere "lead to, bring to, bring along," from ad- "to" (see ad-) + ducere "to lead" (see duke (n.)). Related: Adduced; adducing.
Adelaide: fem. proper name, from French Adélaide, from a Germanic source similar to Old High German Adalhaid, from adal "noble family" (see atheling) + German heit "state, rank," related to Old English -had "person, degree, state, nature" (see -hood). The first element affixed to French fem. ending -ine gave Adeline.
Adeline: fem. proper name, from French, of Germanic origin, literally "noble" (see Adelaide).
Adelphia: district of London, so called because it was laid out by four brothers of a family named Adam, from Greek adelphos "brother," literally "from the same womb," from copulative prefix a- "together with" + delphys "womb," which is perhaps related to dolphin. The district was the site of a popular theater c. 1882-1900, which gave its name to a style of performance.
Aden: place in southern Arabia, ultimately from Akkadian edinnu "plain," which some think also is the root of Biblical Eden.
adenine (n.): crystaline base, 1885, coined by German physiologist/chemist Albrecht Kossel (1853-1927) from Greek aden "gland" (see inguinal) + chemical suffix -ine (2). So called because it was derived from the pancreas of an ox.
adenoid (adj.): 1839, "gland-like," medical Latin adenoideus, from Greek adenoeides, from aden (genitive adenos) "gland" (see inguinal) + eidos "form" (see -oid). Adenoids "adenoid growths" attested by 1856.