Proto-Indo-European root meaning "bird." It also might be the source of *woyo, *oyyo, Proto-Indo-European words for "egg."
It forms all or part of: auspex; auspices; auspicious; avian; aviary; aviation; aviator; avicide; aviculture; aviform; caviar; cockney; egg (n.); ocarina; oo-; oocyte; oolite; oology; osprey; ostrich; oval; ovary; ovate (adj.); oviform; oviparous; ovoviviparous; ovoid; ovulate; ovulation; ovule; ovum.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit vih, Avestan vish, Latin avis "bird;" Greek aietos "eagle;" Old Church Slavonic aja, Russian jajco, Breton ui, Welsh wy, Greek ōon, Latin ovum, Old Norse egg, Old High German ei, Gothic ada all meaning "egg."
early 15c. (implied in adapted) "to fit (something, for some purpose)," from Old French adapter (14c.), from Latin adaptare "adjust, fit to," from ad "to" (see ad-) + aptare "to join," from aptus "fitted" (see apt). Intransitive meaning "to undergo modification so as to fit new circumstances" is from 1956. Related: Adapting.
late 14c., "hard, unbreakable," from adamant (n.). The figurative sense of "unshakeable" (in belief, etc.) is by 1670s. Related: Adamantly; adamance.
"brief, familiar proverb," 1540s, French adage (16c.), from Latin adagium "adage, proverb," apparently a collateral form of adagio, from ad "to" (see ad-) + *agi-, root of aio "I say," which is perhaps cognate with Armenian ar-ac "proverb," asem "to say." But some find this unlikely and suggest the second element might be related to agein "set in motion, drive, urge" (from PIE root *ag- "to drive, draw out or forth, move"). Related: Adagial.
"a very hard stone," mid-14c., adamant, adamaunt, from Old French adamant "diamond; magnet" or directly from Latin adamantem (nominative adamas) "adamant, hardest iron, steel," also used figuratively, of character, from Greek adamas (genitive adamantos), the name of a hypothetical hardest material.
It is a noun use of an adjective meaning "unbreakable, inflexible," which was metaphoric of anything unalterable (such as Hades) and is of uncertain origin. It is perhaps literally "invincible, indomitable," from a- "not" (see a- (3)) + daman "to conquer, to tame," from PIE root *deme- "to constrain, force, break (horses)," for which see tame (adj.). "But semantically, the etymology is rather strange," according to Beekes, who suggests it might be a foreign word altered in Greek by folk etymology, and compares Akkadian (Semitic) adamu.
Applied in antiquity to a metal resembling gold (Plato), white sapphire (Pliny), magnet (Ovid, perhaps through confusion with Latin adamare "to love passionately"), steel, emery stone, and especially diamond, which is a variant of this word. "The name has thus always been of indefinite and fluctuating sense" [Century Dictionary]. The word had been in Old English as aðamans, but the modern word is a re-borrowing.
masc. proper name, the 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." Compare homunculus.
The name also was used to signify the evil inherent in human nature (as a consequence of Adam's fall), and other qualities (e.g. nakedness, gardening) associated with the biblical Adam. Adam's ale for "water" is colloquial from 1640s. To not know(someone)from Adam "not know him at all" is recorded by 1784 (with later elaborations up to from Adam's off ox, 1880). The pet form of the name in Middle English was Addy, hence Addison; other old pet forms (Adkin, Adcock) also survive in surnames.