c. 1200, "to watch with hostile intent, lie in wait for, plot against," from Anglo-French and Old North French waitier "to watch" (Old French gaitier "defend, watch out, be on one's guard; lie in wait for;" Modern French guetter), from Frankish *wahton or another Germanic source, from Proto-Germanic *waht- (source also of Dutch wacht "a watching," Old High German wahten, German wachten "to watch, to guard;" Old High German wahhon "to watch, be awake," Old English wacian "to be awake"), from PIE root *weg- "to be strong, be lively." General sense of "remain in some place" is from late 14c.; that of "to see to it that something occurs" is late 14c. Meaning "to stand by in attendance on" is late 14c.; specific sense of "serve as an attendant at a table" is from 1560s. Related: Waited; waiting.
To wait (something) out "endure a period of waiting" is recorded from 1849. Waiting room is attested from 1680s. Waiting list is recorded from 1841; the verb wait-list "to put (someone) on a waiting list" is recorded from 1960. Waiting game is recorded from 1835, originally in horse-racing.
When speed, not stoutness, is the best of a horse, quite a contrary system is practised. With such a horse, the jockey plays a waiting game; that is, he carefully nurses him through the race, so as not to distress him by overpacing him; as the finish approaches, he creeps up to his horses by degrees, but does not quit them to go in front till he sees that the pace has made them "safe," — when he lets loose and wins. [James Christie Whyte, "History of the British Turf," London, 1840]
c. 1300, "secular tribunal," from Old North French consistorie (Old French consistoire, 12c.) and directly from Late Latin consistorium "waiting room, meeting place of the imperial council," from Latin consistere (see consist). Meaning "Church council, an ecclesiastical court" is from early 14c. Related: Consistorial.
"of or pertaining to a congress," 1690s, from Latin congressionem (from congressus, see congress) + -al (1); specifically "of or pertaining to the Congress of the American states" from 1776. As such the word was at first reviled as barbarous, but Pickering (1816) quotes an unnamed English correspondent: "The term Congress belonging to America, the Americans may employ its derivatives, without waiting for the assent of the English."