1610s, "action of relinquishing to another," from French abandonnement (Old French abandonement), from abandonner "to give up" (see abandon (v.)). Meaning "a deserting, forsaking" (of one's family, principles, etc.) is by 1788; from 1839 as "condition of being forsaken." In law, the relinquishing of a title, privilege, or claim. In music, Italian abbandonatamente is the instruction to play so as to make the time subordinate to the feeling.

1610s, in physiology, a muscle that moves (a limb) away from the axis of the body, from Latin abductor, agent noun from abducere "to lead away," from ab "off, away from" (see ab-) + ducere "to lead" (from PIE root *deuk- "to lead").

1610s, "recoiling (from), strongly opposed to," from Latin abhorentem (nominative abhorrens) "incongruous, inappropriate," present participle of abhorrere "shrink back from, be remote from, be out of harmony with" (see abhor). Meaning "repugnant, loathesome" is from 1650s. Earlier was abhorrable (late 15c.).

"act of sending abroad or away," 1610s, from Latin ablegationem (nominative ablegatio) "a sending off or away," noun of action from past-participle stem of ablegare "send away on a commission," from ab "off, away from" (see ab-) + legare "send with a commission, send as an ambassador" (see legate).

"in open sight, without trickery or disguise," 1610s, from above and board (n.1). "A figurative expression borrowed from gamesters, who, when they put their hands under the table, are changing their cards." [Johnson]

in pathology, "collection of pus in some part of the body," 1610s, from Latin abscessus "an abscess" (the Latin word was used in a medical sense by Celsus), literally "a going away, departure," from the stem of abscedere "withdraw, depart, retire," from ab "off, away from" (see ab-) + cedere "to go, withdraw" (from PIE root *ked- "to go, yield"). The notion is that humors "go from" the body through the pus in the swelling.

"to cut off or away," 1610s, from Latin abscisus, past participle of abscidere "to cut away," from ab "off, away from" (see ab-) + caedere "to cut, cut down" (from PIE root *kae-id- "to strike"). Related: Abscised; abscising.

1610s, "a hastener," from Latin accelerator, agent noun from accelerare "to hasten; make haste" (see accelerate). Motor vehicle sense of "pedal which operates the throttle and thus modulates engine speed" is from 1900; particle physics sense is from 1931.

"upward slope of ground," 1610s, from Latin acclivitatem (nominative acclivitas) "an ascending direction, rising grade, upward steepness," from acclivis "mounting upwards, ascending," from ad "to, up to" (see ad-) + clivus "hill, a slope" (from PIE *klei-wo-, suffixed form of root *klei- "to lean").

1610s, "vouch for, bring into credit," from French accréditer, earlier acrediter, from à "to" (see ad-) + créditer "to credit" (someone with a sum), from crédit "credit" (see credit (n.)). Falsely Latinized in French. The word was rare in English in the original sense but became common in the meaning "confer credit or authority on" (1794). Related: Accredited; accrediting.