"adopt and assimilate an alien culture," 1925 (implied in acculturated), a back-formation from acculturation (q.v.). Acculturize was used from 1895. Related: Acculturating. ETD acculturate (v.).2
late 15c., "that which is heaped up, an accumulated mass," from Latin accumulationem (nominative accumulatio) "a heaping up," noun of action from past-participle stem of accumulare "to heap up, amass," from ad "to," here perhaps emphatic (see ad-), + cumulare "heap up," from cumulus "heap" (from suffixed form of PIE root *keue- "to swell"). Meaning "act of heaping up" is from c. 1600. ETD accumulation (n.).2
"collected into a mass or quantity," 1690s, past-participle adjective from accumulate (v.). The earlier adjective was accumulate (1530s, from Latin past participle accumulatus). ETD accumulated (adj.).2
1520s, "to heap up" (transitive), from Latin accumulatus, past participle of accumulare "to heap up, amass," from ad "to," here perhaps emphatic (see ad-), + cumulare "heap up," from cumulus "heap" (from suffixed form of PIE root *keue- "to swell"). From 1759 in intransitive sense of "grow in size or number." Related: Accumulated; accumulating. ETD accumulate (v.).2
"tending to accumulation; cumulative," 1650s, from Latin stem accumulat- (see accumulate) + -ive. Related: Accumulatively; accumulativeness. ETD accumulative (adj.).2
1610s, "done with care," from Latin accuratus "prepared with care, exact, elaborate," past participle of accurare "take care of," from ad "to" (see ad-) + curare "take care of" (see cure (n.1)). The notion of doing something carefully led to that of being precise (1650s). A stronger word than correct (adj.), weaker than exact (adj.). Related: Accurately; accurateness. ETD accurate (adj.).2
"state of being extremely precise or exact; conformity to truth," 1660s, from accurate + abstract noun suffix -cy. ETD accuracy (n.).2
also accurst, early 13c., acursede "being under a curse," past-participle adjective from obsolete verb acursen "pronounce a curse upon, excommunicate" (late 12c.), from a- intensive prefix (see a- (1)) + cursein "to curse" (see curse (v.)). The unetymological -c- is 15c., a mistaken Latinism in imitation of words in acc-. The weakened sense of "worthy of a curse, damnable" is from 1590s. Related: Accursedly; accursedness. ETD accursed (adj.).2
grammatical case whose primary function is to express destination or goal of motion, mid-15c., from Anglo-French accusatif, Old French acusatif, or directly from Latin (casus) accusativus "(case) of accusing," from accusatus, past participle of accusare "to call to account, make complaint against" (see accuse). ETD accusative (n.).2
The Latin word was chosen somewhat inaccurately to translate Greek (ptōsis) aitiatikē "(case) of that which is caused" based on the similarity of the Greek word to the Greek verb aitiasthai "to accuse." Greek aitia is the root of both, and means "cause" as well as "accusation," hence the confusion of the Romans. A more correct translation would have been casus causativus. ETD accusative (n.).3
Typically it is the case of the direct object, but also sometimes denoting "motion towards." Nouns and adjectives in French, Spanish, and Italian, languages from which English has borrowed heavily, generally were formed from the accusative case of a Latin word. Related: Accusatival; accusatively. ETD accusative (n.).4
c. 1300, "charge (with an offense, fault, error, etc.), impugn, blame," from Old French acuser "to accuse, indict, reproach, blame" (13c., Modern French accuser), earlier "announce, report, disclose" (12c.), or directly from Latin accusare "to call to account, make complaint against, reproach, blame; bring to trial, prosecute, arraign indict," from the phrase ad causa, from ad "with regard to" (see ad-) + causa "a cause; a lawsuit" (see cause (n.)). "Accuse commonly, though not invariably, expresses something more formal and grave than charge" [Century Dictionary, 1902]. Related: Accused; accusing; accusingly. ETD accuse (v.).2
"person charged with a crime," 1590s, from past participle of accuse (v.). ETD accused (n.).2
late 14c., accusacioun, "charge of wrongdoing," from Old French acusacion "charge, indictment" (Modern French accusation) or directly from Latin accusationem (nominative accusatio) "formal complaint, indictment," noun of action from past-participle stem of accusare "call to account, make complaint against," from ad causa, from ad "with regard to" (see ad-) + causa "a cause; a lawsuit" (see cause (n.)). The meaning "that which is charged (against someone)" is from early 15c. ETD accusation (n.).2
"one who accuses or blames," especially "person who formally accuses another of an offense before a magistrate," mid-14c., accusour, from Anglo-French accusour, Old French accusor, from Latin accusator, agent-noun from past-participle stem of accusare (see accuse). ETD accuser (n.).2
c. 1600, "containing an accusation," from Latin accusatorius "of a prosecutor, relating to prosecution; making a complaint," from accusare "call to account, make complaint against" (see accuse). Related: Accusatorial (1801); accusatorially. ETD accusatory (adj.).2
late 15c., "made customary, habitual, often practiced or used," past-participle adjective from accustom (v.). ETD accustomed (adj.).2
"familiarize by custom or use," early 15c., accustomen, from Old French acostumer "become accustomed; accustom, bring into use" (12c., Modern French accoutumer), from à "to" (see ad-) + verb from costume "habit, practice" (see custom (n.)). Related: Accustomed; accustoming. ETD accustom (v.).2
electronics abbreviation of alternating current/direct current, by 1898. As slang for "bisexual," 1959, said to have been in use orally from c. 1940; the notion is of working both ways. ETD AC/DC (adj.).2
word-forming element in Modern Latin making names for orders and classes in zoology (Crustacea, Cetacea, etc.), from Latin -acea, neuter plural of -aceus "belonging to, of the nature of" (enlarged from adjectival suffix -ax, genitive -acis). ETD -acea.2
The names are thus formally adjectives, Latin animalia "animals" (a neuter plural noun) being understood. Thus Crustacea "shellfish" are *crustacea animalia "crusty animals." ETD -acea.3
In botany, the suffix is -aceae, from the fem. plural of -aceus, forming orders or families of plants (Rosaceae, etc.) with a presumed plantae "plants," which is a fem. plural. ETD -acea.4
late 14c., name of the potter's field near Jerusalem that was purchased with the money Judas Iscariot took to betray Jesus, literally "place of bloodshed," from Greek Akeldama, rendering an Aramaic (Semitic) name akin to Syriac haqal dema "the field of blood." So called for being purchased with the blood-money. ETD Aceldama.2
"having no center," 1852; see a- (3) "not" + -centric. ETD acentric (adj.).2
word-forming element denoting "belonging to, of the nature of," from Latin -aceus, enlarged form of adjectival suffix -ax (genitive -acis); see -acea. Especially in biology, "pertaining to X order of plants or animals." ETD -aceous.2
"headless," 1731, from French acéphale + -ous or directly from Late Latin acephalus, from Greek akephalos. See a- (3) "not" + cephalo- "head." ETD acephalous (adj.).2
Principally in botany and zoology, but also "without a leader" (1751). Acephali as the name of a fabulous race of men with no heads, said by ancient writers to inhabit part of Africa, is attested from c. 1600, from Late Latin plural of acephalus, from Greek akephalos; the name also appears in Church history in reference to sects that refused to have priests or bishops (1620s). Related: Acephalian (1580s); acephalic (1650s). ETD acephalous (adj.).3
maple tree genus name, from Latin acer, a word of uncertain origin, perhaps from PIE *ak- "be sharp" (see acro-) and so called for its pointed leaves. ETD acer (n.).2
There seem to have been two roots for "maple" in Indo-European; cognates of this one are said to include Old High German ahorn "maple," and there is a similar form in Greek akastos "maple," perhaps also Hittite hiqqar- "maple." De Vaan writes, "This may well be a non-PIE tree name which was borrowed into Greek and Latin." ETD acer (n.).3
"sourness, with roughness or astringency of taste," 1570s, from French acerbité, from Latin acerbitatem (nominative acerbitas) "harshness, sharpness, bitterness, sourness," literal and figurative (as in virus acerbitatis "the poison of malice"), from acerbus "bitter to taste, sharp, sour, tart," from Proto-Italic *akro-po- "sharp" (from PIE root *ak- "be sharp, rise (out) to a point, pierce"). ETD acerbity (n.).2
The earliest use in English is figurative, of "sharp and bitter" persons. Of tastes, from 1610s. Latin acerbus is related to acer "sharp" as superbus "haughty" to super "above." ETD acerbity (n.).3
1865, originally, and usually, figurative: "sour, harsh, severe" (of speech, manners, etc.), from Latin acerbus "harsh to the taste, sharp, bitter, sour," especially of unripe fruits, etc., also figuratively, of character, conduct, etc. (see acerbity) + -ic. The earlier adjective was simply acerb (1650s), from French acerbe, from Latin acerbus. ETD acerbic (adj.).2
"to heap up," 1610s, from Latin acervatus, past participle of acervare "to heap up," from acervus "heap," which is akin to acer "sharp" (from PIE root *ak- "be sharp, rise (out) to a point"). Related: Acervated; acervating; acerval; acervative; acervuline "occurring in clusters; clustered" (by 1859). ETD acervate (v.).2
"brain-sand" (anatomical), 1806, medical Latin, literally "little heap," diminutive of Latin acervus "heap," which is akin to acer "sharp" (from PIE root *ak- "be sharp, rise (out) to a point"). Compare acervate. ETD acervulus (n.).2
"becoming sour," 1670s, from French acescent, from Latin acescentem (nominative acescens), present participle of acescere "become sour," from acer "sharp" (from PIE root *ak- "be sharp, rise (out) to a point, pierce"). ETD acescent (adj.).2
by 1790 in a translation of Fourcroy, "salt formed by combining acetic acid with a base," from Latin acetum "vinegar" (see acetic) + chemical suffix -ate (3). As a type of synthetic material, it is attested from 1920, short for acetate silk (1912), etc. ETD acetate (n.).2
1808 (in acetic acid), from French acétique "pertaining to vinegar, sour, having the properties of vinegar," from Latin acetum "vinegar" (properly vinum acetum "wine turned sour;" see vinegar), originally the past participle of acere "be sharp; be sour" (related to acer "sharp," from PIE root *ak- "be sharp, rise (out) to a point, pierce"). ETD acetic (adj.).2
U.S. name for "para-acetylaminophenol," 1960, composed of syllables from the chemical name: acetyl, a derivative of acetic (q.v.; also see acetylene) + amino- + phenol. In Britain, the same substance is paracetamol. ETD acetaminophen (n.).2
"process of turning to vinegar," 1753, from Latin acetum "vinegar" (see acetic) + -fication, word-forming element indicating "making or causing." ETD acetification (adj.).2
before vowels acet-, word-forming element from acetic and generally indicating compounds from or related to acetic acid , thus ultimately from Latin acetum "vinegar." ETD aceto-.2
colorless volatile liquid, 1839, literally "a derivative of acetic acid," from Latin acetum "vinegar" (see acetic) + Greek-based chemical suffix -one, which owes its use in chemistry to this word. ETD acetone (n.).2
gaseous hydrocarbon, 1860, from French acétylène, coined by French chemist Pierre Eugène Marcellin Berthelot from chemical ending -ene + acetyl, which was coined from acetic + -yl in 1839 by German chemist Justus von Liebig. Liebig's coinage was in reference to a different radical; acetyl was transferred to its current sense in 1850s, but Berthelot's coinage was based on the original use of acetyl. ETD acetylene (n.).2
Middle English aken, from Old English acan "suffer continued pain," from Proto-Germanic *akanan, which is perhaps from a PIE root *ag-es- "fault, guilt," with apparent cognates in Sanskrit and Greek, which itself is perhaps imitative of groaning. ETD ache (v.).2
Originally the verb was pronounced "ake," the noun "ache" (as in speak/speech). The noun changed its pronunciation to conform to the verb, but the spelling of both was changed to ache c. 1700 on a false assumption of a Greek origin (specifically Greek akhos "pain, distress," which rather is a distant relation of awe (n.)). Related: Ached; aching. ETD ache (v.).3
aspirated form of ah; in English often used in representations of German or Celtic speech. ETD ach (interj.).2
"continuing pain," early 15c., æche, ece "an ache, pain," from Old English æce, from Proto-Germanic *akiz, from same source as ache (v.), which see for the unusual evolution of spelling and pronunciation. ETD ache (n.).2
in Homeric language, "a Greek," generally; later restricted to natives or inhabitants of Achaea, a region in the Peloponnesus. The Achaean League after c. 280 B.C.E. was a model for later federal republics. In Latin, Achaicus meant "a Greek." ETD Achaean.2
name of the armor-bearer and faithful friend of Aeneas in the "Aeneid;" The phrase fidus Achates was proverbial for "faithful friend, loyal and devoted companion." The name is from Greek akhatēs "agate" (see agate). ETD Achates.2
1580s, fabled river of the Lower World in Greek mythology, from Greek Akheron, the name of several real rivers in addition to being the mythical river of the Underworld. The name perhaps means "forming lakes" (compare Greek akherousai "marsh-like water"), from PIE root *eghero- "lake" (source of Lithuanian ežeras, ažeras, Old Prussian assaran, Old Church Slavonic jezero "lake"). ETD Acheron.2
The derivation from Greek akhos "woe" is considered folk etymology. The name later was given to certain rivers in Greece and Italy because they flowed through dismal surroundings or disappeared underground and were thought to be gateways to the Underworld. Related: Acherontic. ETD Acheron.3
"full of aches, sore, aching," 1875, first recorded in George Eliot's letters, from ache (n.) + -y (2). Middle English had akeful "painful" (early 15c.). Related: Achily; achiness. ETD achy (adj.).2
"capable of being gained or performed," 1620s; see achieve (v.) + -able. Related: Achievably; achievableness; achievability. ETD achievable (adj.).2
late 15c., "act of completing" (something), from French achèvement "a finishing," noun of action from Old French achever "to finish, accomplish" (see achieve). Meaning "thing achieved" is recorded from 1590s. ETD achievement (n.).2
early 14c., acheven, "to perform, execute, accomplish;" late 14c., "gain as a result of effort," from Old French achever (12c.) "to finish, accomplish, complete," from phrase à chef (venir) "at an end, finished," or Vulgar Latin *accapare, from Late Latin ad caput (venire); both the French and Late Latin phrases meaning literally "to come to a head," from ad "to" (see ad-) + stem of Latin caput "head" (from PIE root *kaput- "head"). ETD achieve (v.).2
Related: Achieved; achieving. ETD achieve (v.).3
Greek hero of the Trojan War stories, bravest, swiftest, and handsomest of Agamemnon's army before Troy, he was son of Thetis and Peleus. His name is perhaps a compound of akhos "pain, grief" (see awe) + laos "the people, a people" (see lay (adj.)); or else it is from Pre-Greek (non-IE). Related: Achillean. ETD Achilles.2
from Modern Latin tendo Achillis, first used by German surgeon Lorenz Heister (1683-1758) and so-called in reference to the one vulnerable spot of the Greek hero Achilles, whose mother held him by the heel when she dipped him in the River Styx to render him invulnerable (this story is not in Homer and not found before 1c. C.E.). Earlier Achilles' sinew, from Modern Latin chorda Achillis, coined 1693 by Dutch anatomist Philip Verheyden when dissecting his own amputated leg. Hence figurative use of heel of Achillies for "vulnerable spot" (1810). ETD Achilles tendon (n.).2
"destitute of color; transmitting light without decomposing it into constituent colors," 1766, from a- (3) "not, without" + chromatic. Related: Achromatically. ETD achromatic (adj.).2
in English writing, a characteristic German word used to command attention, from German achtung, from acht (n.) "attention, care, heed, consideration," achten (v.) "pay attention to, regard, esteem, respect," from Old High German ahton "pay attention to," a general Germanic word akin to Old English eahtian "to estimate, esteem, consider, praise," but with no living native descendants in English. ETD achtung (interj.).2
word-forming element making nouns of quality, state, or condition, a confusion in English of three similar suffixes from Latin: ETD -acy.2
1. in primacy, etc., from Old French -acie and directly from Medieval Latin -acia, Late Latin -atia, making nouns of quality, state, or condition from nouns in -as. ETD -acy.3
2. in advocacy, etc., from Late Latin -atia, forming nouns of state from nouns in -atus. ETD -acy.4
3. in fallacy, etc., from Latin -acia, forming nouns of quality from adjectives in -ax (genitive -acis). Also forming part of -cracy. It has been extended in English to nouns not found in Latin (accuracy) and to non-Latin words (piracy). ETD -acy.5
"resembling or in the form of small needles," 1794, from Latin acicula "needle, small pin," diminutive of acus "pin" (from PIE root *ak- "be sharp, rise (out) to a point, pierce"). ETD acicular (adj.).2
1690s, from acid (adj.); originally loosely applied to any substance having a sour taste like vinegar, in modern chemistry it was gradually given more precise definitions from early 18c. and is given to many compounds which do not have such a taste. ETD acid (n.).2
The slang meaning "LSD-25" first recorded 1966 (see LSD). ETD acid (n.).3
Acid rock (type performed or received by people using LSD) is also from 1966; acid house dance music style is 1988, probably from acid in the hallucinogenic sense + house "dance club DJ music style." ETD acid (n.).4
1620s, "of the taste of vinegar," from French acide (16c.) or directly from Latin acidus "sour, sharp, tart" (also figurative, "disagreeable," etc.), adjective of state from acere "to be sour, be sharp" (from PIE root *ak- "be sharp, rise (out) to a point, pierce"). ETD acid (adj.).2
Figurative use in English ("sour, sharp, biting") is from 1775; the word was applied to intense colors by 1916; an acid dye (1888) involves an acid bath. Acid rain "highly acidity in rain caused by atmospheric pollution" is recorded by 1859 in reference to England. Acid drop as a kind of hard sugar candy flavored with tartaric acid is by 1835, with drop (n.) in the "lozenge" sense. ETD acid (adj.).3
Acid test is American English, 1881, in literal use a quick way to distinguish gold from similar metals by application of nitric acid. Fowler wrote (1920) that it was then in vogue in the figurative sense and "became familiar through a conspicuous use of it during the war by President Wilson." ETD acid (adj.).4
"containing a large amount of the acid element," 1877, originally in geology; see acid (n.) + -ic. The geological use was chemical, in reference to the acid element (silicon, etc.) in certain salts, and was opposed to basic. ETD acidic (adj.).2
"quality of being acid or sour; tartness," 1610s, from French acidité (16c.) or directly from Latin aciditatem (nominative aciditas) "sourness," noun of quality from Latin acidus "sour, tart" (see acid (adj.)). ETD acidity (n.).2
"make acid; become acid; render sour," literally or figuratively, 1784 (implied in acidifying); see acid (adj.) + -ify. Related: Acidified. ETD acidify (v.).2
1920, used of milk fermented by acidophilic bacteria, from acidophil (1900), indicating "easily stained by acid dyes," a hybrid word, from Latin acidus "acidic, sour, tart" (see acid (adj.)) + Greek philos "loving" (see -phile); the bacteria so called because they stain easily with an acid dye. ETD acidophilus (adj.).2
"sub-acidic, slightly sour" (of cream of tartar, oranges, etc.), 1766, also used figuratively for "sour-tempered;" from Latin acidulus "slightly sour," a diminutive of acidus (see acid (adj.)). ETD acidulous (adj.).2
"make somewhat sour, flavor with an acid," 1704 (implied in acidulated), from Latin acidulus "slightly sour" (see acidulous) + -ate (2). Related: Acidulating; acidulent. ETD acidulate (v.).2
compound adjectival word-forming element of Latin origin, attached to verb stems and expressing intensity of action: "given to, inclined to, abounding in," or expressing intensity of physical or mental action, from Latin -aci- (nominative -ax, accusative -acem), noun ending used with verbal stems (see -acea), + -ous. The accompanying nouns are formed in -acity. ETD -acious.2
British oral code for letter -a- in wireless and telephone communication, 1898; hence ack-ack "anti-aircraft" (gun, fire, etc.). Compare toc (-t-), emma (-m-). ETD ack.2
1939, representing A.A., the military abbreviation for anti-aircraft (see ack). ETD ack-ack.2
late 15c., "admit or show one's knowledge," a blend of Middle English aknow "admit or show one's knowledge" and Middle English knowlechen "admit, acknowledge" (c. 1200; see knowledge). Middle English aknow is from Old English oncnawan "understand, come to recognize," from on (see on (prep.)) + cnawan "recognize;" see know). ETD acknowledge (v.).2
"By 16th c. the earlier vbs. knowledge and a(c)know ... were obs., and acknowledge took their place" [OED]. In the merger, an unetymological -c- slipped in; perhaps the explanation is that when English kn- became a simple "n" sound, the -c- stepped up to preserve, in this word, the ancient "kn-" sound. Related: Acknowledged; acknowledging. ETD acknowledge (v.).3
alternative spelling of acknowledgement. OED deems it "a spelling more in accordance with Eng[lish] values of letters." Compare judgment. ETD acknowledgment (n.).2
1590s, "act of acknowledging," from acknowledge + -ment. "An early instance of -ment added to an orig. Eng. vb." [OED]. Meaning "token of due recognition" is recorded from 1610s. ETD acknowledgement (n.).2
also A.C.L.U., abbreviation of American Civil Liberties Union. ETD ACLU.2
"highest point," 1560s, from Greek akmē "(highest) point, edge; peak of anything," hence "prime (of life, etc.), the best time" (from PIE *ak-ma-, suffixed form of root *ak- "be sharp, rise (out) to a point, pierce"). In English it was written in Greek letters until c. 1620. The U.S. grocery store chain was founded 1891 in Philadelphia, Pennsylvania. ETD acme (n.).2
skin eruption common during puberty, 1813, from Modern Latin, from aknas, a 6c. Latin clerical misreading of Greek akmas, accusative plural of akmē "point" (see acme), from PIE root *ak- "be sharp, rise (out) to a point, pierce." The "pointed" pimples are the source of the medical use. ETD acne (n.).2
"cold," early 14c.; see a- (1), here perhaps intensive + cold (adj.). Or it might be literally "a-cooled," from the past participle of the verb acool "to take cold" (late Old English); "to make cold" (15c.). ETD acold (adj.).2
early 14c., "inferior officer in the church," from Old French acolite or directly from Medieval Latin acolytus (Late Latin acoluthus), from Greek akolouthos "following, attending on," as a noun, "a follower, attendant," literally "having one way," from a- "together with," copulative prefix (see a- (3)), + keleuthos "a way, road, path, course, journey," which is of unknown etymology. The word was in late Old English as acolitus, a Latin form; in early modern English a corrected form acolythe was used. ETD acolyte (n.).2
"baldness, want or deficiency of hair," a medical term, by 1860, a coinage in Modern Latin from abstract noun suffix -ia (see -ia) + Latinized form of Greek akomos "hairless, bald," from a- "not, without" (see a- (3)) + komē "hair" (see comet). ETD acomia (n.).2
poisonous plant (also known as monkshood and wolfsbane), 1570s, from French aconit (16c.), from Latin aconitum, from Greek akoniton, which is of unknown origin. ETD aconite (n.).2
The highly poisonous alkaloid in it, once isolated, was named aconitine (1826). The ancient folk-etymology of the name is Derived by the ancients from Greek akoniti "without dust," hence "without struggle or fight," hence "invincible" in its deadly effect. But Beekes finds this "hardly possible" and proposes a substrate origin. ETD aconite (n.).3
Middle English akorn, from Old English æcern "nut, mast of trees, acorn," a common Germanic word (cognates: Old Norse akarn, Dutch aker, Low German ecker "acorn," German Ecker, Gothic akran "fruit"), originally the mast of any forest tree. It is by most sources said to be related to Proto-Germanic *akraz, the source of Old English æcer "open land," Gothic akrs "field," Old French aigrun "fruits and vegetables" (from Frankish or some other Germanic source), perhaps on the notion of "fruit of the open or unenclosed land;" see acre. ETD acorn (n.).2
The sense was gradually restricted in Low German, Scandinavian, and English to the most important of the forest produce for feeding swine: the mast of the oak tree. The regular modern form would be *akern; the current spelling emerged 15c.-16c. by folk etymology association with oak (Old English ac) and corn (n.1), neither of which has anything to do with it. Acorn squash is attested by 1937. ETD acorn (n.).3
1680s, "the science of sound," from acoustic; also see -ics. The meaning "acoustic properties" of a building, etc., is attested from 1885. ETD acoustics (n.).2
c. 1600, "pertaining to hearing or sound," from French acoustique, from Latinized form of Greek akoustikos "pertaining to hearing," from akoustos "heard, audible," verbal adjective from akouein "to hear," which probably is from copulative prefix a- (see a- (3)) + koein "to mark, perceive, hear" (from PIE root *kous- "to hear," which is also the presumed source of English hear). ETD acoustic (adj.).2
In reference to material meant to deaden sound, 1924. Of sound reproduced mechanically (rather than electrically) from 1932 in reference to gramophone players; acoustic guitar (as distinguished from electric) is attested by 1958. Related: Acoustical; acoustically. ETD acoustic (adj.).3
c. 1300, "state of being acquainted;" late 14c., "person with whom one is acquainted;" also "personal knowledge;" from Old French acointance "acquaintance, friendship, familiarity," noun of action from acointer "make known" (see acquaint). Acquaintant (17c.), would have been better in the "person known" sense but is now obsolete. Fowler regards acquaintanceship (1792) as a "needless variant." ETD acquaintance (n.).2
early 13c., "personally known;" past-participle adjective from acquaint (v.). Of skills, situations, etc., from late 15c. ETD acquainted (adj.).2
Acquaint also was used as an adjective (late 13c.) "acquainted." ETD acquainted (adj.).3
early 13c., "make oneself known" (reflexive, now obsolete); early 14c., "to gain for oneself personal knowledge of," from Old French acointer "make known; make or seek acquaintance of," from Vulgar Latin *accognitare "to make known," from Latin accognitus "acquainted with," past participle of accognoscere "know well," from ad "to" (see ad-) + cognitus, past participle of cognoscere "come to know" (see cognizance). ETD acquaint (v.).2
Meaning "to inform (someone of something), furnish with knowledge or information" is from 1550s. Related: Acquainted; acquainting. ETD acquaint (v.).3
1610s, "remain at rest" (a sense now obsolete); 1650s as "agree tacitly, concur," from French acquiescer "to yield or agree to; be at rest," (14c.), from Latin acquiescere/adquiescere "become quiet, remain at rest, rest, repose," thus "be satisfied with, be content," from ad "to" (see ad-) + quiescere "become quiet," from quies (genitive quietis) "rest, quiet" (from PIE root *kweie- "to rest, be quiet"). Related: Acquiesced; acquiescing. ETD acquiesce (v.).2
1630s, "rest, quiet, satisfaction," from French acquiescence, noun of action from acquiescer "to yield or agree to; be at rest" (see acquiesce). Meaning "silent consent, passive assent" is recorded from 1640s. ETD acquiescence (n.).2
"disposed to yield, submissive," 1690s (implied in acquiescently), from Latin acquiescentem (nominative acquiescens), present participle of acquiescere "become quiet, remain at rest" (see acquiesce). ETD acquiescent (adj.).2
"to get or gain, obtain," mid-15c., acqueren, from Old French aquerre "acquire, gain, earn, procure" (12c., Modern French acquérir), from Vulgar Latin *acquaerere, corresponding to Latin acquirere/adquirere "to get in addition to, accumulate, gain," from ad "to," here perhaps emphatic (see ad-), + quaerere "to seek to obtain" (see query (v.)). Reborrowed in current form from Latin c. 1600. Related: Acquired; acquiring. ETD acquire (v.).2
c. 1600, "gained by effort," past-participle adjective from acquire. Of diseases, "occurring after birth, thus not dependent on heredity," 1842 (opposed to congenital); acquired immune deficiency is attested by 1980; acquired immune deficiency syndrome by 1982. Acquired taste is attested from 1734. ETD acquired (adj.).2
"act of acquiring; that which is acquired," 1620s, from acquire + -ment. Perhaps modeled on French acquerement (16c.). ETD acquirement (n.).2
1630s, "owned through acquisition" (now obsolete, this sense going with acquired), from Latin acquisit-, past-participle stem of acquirere "accumulate, gain" (see acquire) + -ive. Meaning "given to acquisition, avaricious" is by 1824. Related: Acquisitively (1590s); acquisitiveness. ETD acquisitive (adj.).2
late 14c., adquisicioun, "act of obtaining," from Old French acquisicion "purchase, acquirement" (13c., Modern French acquisition) or directly from Latin acquisitionem (nominative acquisitio), noun of action from past-participle stem of acquirere "get in addition, accumulate," from ad "to," here perhaps emphatic (see ad-), + quaerere "to seek to obtain" (see query (v.)). ETD acquisition (n.).2
The meaning "thing obtained" is from late 15c. The vowel change of -ae- to -i- in Latin is due to a phonetic rule in that language involving unaccented syllables in compounds. ETD acquisition (n.).3
mid-13c., aquiten, "repay, reciprocate, reward or retaliate for" (a good or bad deed); c. 1300 as "satisfy a debt; redeem (a pledge)," from Old French aquiter, acquiter "pay, pay up, settle a claim" (12c., Modern French acquitter), from a- "to" (see ad-) + quite "free, clear," from Medieval Latin quitus, quittus, from Latin quietus "free" (in Medieval Latin "free from war, debts, etc."), also "calm, resting" (from PIE root *kweie- "to rest, be quiet"). Also in part from Medieval Latin acquitare. ETD acquit (v.).2
From mid-14c. as "relieve (someone) of an obligation, release from a pledge," hence the meanings "set (an accused person) free from charges, pronounce not guilty," and "discharge one's duty; behave or conduct oneself" (for better or worse), all of which date to late 14c. The notion in the word is "to release or discharge," from an obligation or from accusation, guilt, censure, or suspicion. Related: Acquitted; acquitting. ETD acquit (v.).3
"freed, exonerated," 1670s, past-participle adjective from acquit (v.). Formerly in this sense was acquit (late 14c.). ETD acquitted (adj.).2
early 15c., aquitaille, "payment of debt or retribution;" see acquit + -al (2). Sense of "a release from debt or obligation" is from mid-15c.; that of "freeing from charge or offense" (by legal process) is from 1530s. ETD acquittal (n.).2
"legal settlement" of a debt, obligation, etc., early 14c., aquitaunce, from Old French aquitance and Medieval Latin acquietantia; see acquit + -ance. ETD acquittance (n.).2
Old English æcer "tilled field, open land," from Proto-Germanic *akraz "field, pasture" (source also of Old Norse akr, Old Saxon akkar, Old Frisian ekker, Middle Dutch acker, Dutch akker, Old High German achar, German acker, Gothic akrs "field"), from PIE root *agro- "field." ETD acre (n.).2
"[O]riginally 'open country, untenanted land, forest'; ... then, with advance in the agricultural state, pasture land, tilled land, an enclosed or defined piece of land" [OED]. In English at first without reference to dimension; in late Old English the amount of land a yoke of oxen could plow in a day, afterward defined by statute 13c. and later as a piece 40 poles by 4, or an equivalent shape [OED cites 5 Edw. I, 31 Edw. III, 24 Hen. VIII]. The older sense is retained in God's acre "churchyard." ETD acre (n.).3
The Germanic word was adopted early in Old French and Medieval Latin, hence the Modern English spelling, which by normal development would be *aker (compare baker from Old English bæcere). ETD acre (n.).4
"number of acres in a tract of land," 1795, from acre + -age. ETD acreage (n.).2
"quality of being acrid," 1799, from acrid + -ity. Acridness (1759) is older. ETD acridity (n.).2
1712, "sharp and bitter to the taste," formed irregularly (perhaps by influence of acrimonious) from Latin acer (fem. acris) "sharp to the senses, pungent, bitter; eager, fierce," also figuratively, of qualities, "active, ardent, spirited," also "hasty, quick, passionate;" of mind "violent, vehement; subtle, penetrating," from PIE *akri- "sharp," from root *ak- "be sharp, rise (out) to a point, pierce." Of feelings, temper, etc., in English from 1781. The -id suffix probably is in imitation of acid. Acrious (1670s) is a correct formation, but seldom seen. Related: Acridly. ETD acrid (adj.).2
1540s, "quality of being sharp or pungent in taste," from French acrimonie or directly from Latin acrimonia "sharpness, pungency of taste," figuratively "acrimony, severity, energy," abstract noun from acer "sharp" (fem. acris), from PIE root *ak- "be sharp, rise (out) to a point, pierce") + -monia suffix of action, state, condition (see -mony). Figurative extension to personal sharpness or bitterness is by 1610s. ETD acrimony (n.).2
1610s, "acrid," from French acrimonieux, from Medieval Latin acrimoniosus, from Latin acrimonia "sharpness" (see acrimony). Now usually figurative, of dispositions, debates, etc., "bitter, irritating in manner" (1775). Related: Acrimoniously; acrimoniousness. ETD acrimonious (adj.).2
word-forming element meaning "highest, topmost, at the extremities," before vowels acr-, from Latinized form of Greek akro- "pertaining to an end, extreme," from akros "at the end, at the top, outermost; consummate, excellent" (from PIE *akri-, from root *ak- "be sharp, rise (out) to a point, pierce"). ETD acro-.2
1845, from French acrobate "tightrope-walker" (14c.) and directly from a Latinized form of Greek akrobatēs "rope dancer, gymnastic performer," which is related to akrobatos "going on tip-toe, climbing up high," from akros "topmost, at the point end" (from PIE root *ak- "be sharp, rise (out) to a point, pierce") + Greek agential element -batēs "one that goes, one that treads (in some manner), one that is based," from -batos, verbal adjective from stem of bainein "to go, walk, step" (from PIE root *gwa- "to go, come"). ETD acrobat (n.).2
1859, "acrobatic performances or feats," from acrobatic; also see -ics. Also acrobatism (1864). Acrobacy (1918, from French acrobatie) sometimes was used. Figurative use is attested by 1915. ETD acrobatics (n.).2
"of or pertaining to an acrobat or an acrobat's performances," 1848; see acrobat + -ic, probably modeled on French acrobatique. Related: Acrobatically. ETD acrobatic (adj.).2
"gigantism due to activity of pituitary after normal growth has ceased," 1886, from French acromégalie, from medical Latin acromegalia, from Greek akron "extremity, highest point, mountain peak, headland," neuter of akros "at the furthest point" (from PIE root *ak- "be sharp, rise (out) to a point, pierce") + megas "great" (fem. megale; from PIE root *meg- "great"). Said in contemporary literature to have been coined 1885 by French physician Dr. Pierre Marie. ETD acromegaly (n.).2