1540s, "to disown, disinherit (children)," from Latin abdicatus, past participle of abdicare "to disown, disavow, reject" (specifically abdicare magistratu "renounce office"), literally "proclaim as not belonging to one," from ab "off, away from" (see ab-) + dicare "proclaim" (from PIE root *deik- "to show," also "pronounce solemnly," and see diction). Meaning "divest oneself of office, privilege, etc., before the term expires" is recorded by 1610s in English (it was in classical Latin). Related: Abdicated; abdicating.

1540s, "flesh or meat of the belly" (a sense now obsolete), from Latin abdomen "the belly," a word of unknown origin, Perhaps [OED, Watkins] from abdere "conceal" (from ab "off, away" + PIE root *dhe- "to set, put"), with a sense of "concealment of the viscera," or else "what is concealed" by proper dress. De Vaan, however, finds this derivation "unfounded." Anatomical sense of "part of the mammalian body between the diaphragm and the pelvis" is from 1610s. Zoological sense of "posterior division of the bodies of arthropods" is by 1725.

1540s, "the expulsion of the fetus before it is viable," originally of deliberate as well as unintended miscarriages; from Latin abortionem (nominative abortio) "miscarriage; abortion, procuring of an untimely birth," noun of action from past-participle stem of aboriri "to miscarry, be aborted, fail, disappear, pass away," a compound word used in Latin for deaths, miscarriages, sunsets, etc., which according to OED is from ab, here as "amiss" (see ab-), + stem of oriri "appear, be born, arise" (see origin).

Meaning "product of an untimely birth" is from 1630s; earlier in this sense was abortive (early 14c.). Another earlier noun in English for "miscarriage" was abort (early 15c.). In the Middle English translation of Guy de Chauliac's "Grande Chirurgie" (early 15c.) Latin aborsum is used for "stillbirth, forced abortion." Abortment is attested from c. 1600; aborsement from 1530s, both archaic. Aborticide (1875) is illogical. Compare miscarriage.

In 19c. some effort was made to distinguish abortion "expulsion of the fetus between 6 weeks and 6 months" from miscarriage (the same within 6 weeks of conception) and premature labor (delivery after 6 months but before due time). The deliberate miscarriage was criminal abortion. This broke down late 19c. as abortion came to be used principally for intentional miscarriages, probably via phrases such as procure an abortion.

Criminal abortion is premeditated or intentional abortion procured, at any of pregnancy, by artificial means, and solely for the purpose of preventing the birth of a living child : feticide. At common law the criminality depended on the abortion being caused after quickening. [Century Dictionary, 1899]

Foeticide (n.) appears 1823 as a forensic medical term for deliberate premature fatal expulsion of the fetus; also compare prolicide. Another 19c. medical term for it was embryoctony, with second element from a Latinized form of Greek kteinein "to destroy." Abortion was a taboo word for much of early 20c., disguised in print as criminal operation (U.S.) or illegal operation (U.K.), and replaced by miscarriage in film versions of novels. Abortium "hospital specializing in abortions," is from 1934, in a Soviet Union context.

1540s, "to draw away, withdraw, remove" (transitive), from Latin abstractus or else from abstract (adj.). From 1610s in the philosophical sense "consider as a general object or idea without regard to matter." Related: Abstracted; abstracting.

1540s, type of shrub or tree fund in warm climates of Africa and Australia, from Latin acacia, from Greek akakia "thorny Egyptian tree," a word of uncertain origin. Perhaps it is related to Greek akē "point, thorn" (from PIE root *ak- "be sharp, rise (out) to a point, pierce"), or perhaps it is a Hellenization of some Egyptian word. Beekes suggests it is probably a word from a pre-Greek Mediterranean language and finds "no reason for an Oriental origin." Greek kaktos also has been compared. From late 14c. in English as the name of a type of gum used as an astringent, etc. Extended 17c. to North American trees.

1540s, "act of shouting or applauding in approval," from Latin acclamationem (nominative acclamatio) "a calling, exclamation, shout of approval," noun of action from past-participle stem of acclamare "to call to, cry out at, shout approval or disapproval of," from assimilated form of ad "to, toward" (see ad-) + clamare "cry out" (from PIE root *kele- (2) "to shout"). As a method of spontaneous approval of resolutions, etc., by unanimous voice vote, by 1801, probably from the French Revolution.

usually plural, accoutrements, "personal clothing and equipment," 1540s, from French accoustrement (Modern French accoutrement), from accoustrer, from Old French acostrer "arrange, dispose, put on (clothing)," probably originally "sew up" (see accouter).

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.

"brief, familiar proverb," 1540s, French adage (16c.), from Latin adagium "adage, proverb," apparently a collateral form of adagio, according to Watkins, from ad "to" (see ad-) + *agi-, root of aio "I say," which is perhaps cognate with Armenian ar-ac "proverb," asem "to say." But de Vaan says of the Latin word group that "word-internal a and their sporadic, relatively late attestation suggest that they were derived from adigo 'to drive, force'," related to agein "set in motion, drive, urge" (from PIE root *ag- "to drive, draw out or forth, move"). Related: Adagial.

1540s, "act of paying divine honors," from French adoration, from Late Latin adorationem (nominative adoratio) "worship, adoration," noun of action from past-participle stem of adorare "to worship." See adore, the original sense of which is preserved in this word.