late 13c., auys "opinion," from Old French avis "opinion, view, judgment, idea" (13c.), from phrase ço m'est à vis "it seems to me," or from Vulgar Latin *mi est visum "in my view," ultimately from Latin visum, neuter past participle of videre "to see" (from PIE root *weid- "to see"). Meaning "opinion offered as worthy to be followed, counsel" is from late 14c.
The unetymological -d- (on model of Latin words in ad-) was inserted occasionally in French by scribes 14c.-16c. and was made regular in English 15c. by Caxton. Substitution of -c- for -s- is 18c., to preserve the breath sound and to distinguish from advise. Early Modern English tended to alternate -ce and -se endings in otherwise confusable noun-verb pairs, using -se for the verb and -ce for the noun: devise/device, peace/appease, practice/practise, license/licence, prophecy/prophesy.
early 14c., avisement, "examination, inspection, observation," from Old French avisement "consideration, reflection; counsel, advice," from aviser "deliberate, reflect, consider," from avis "opinion" (see advice). Meaning "advice, counsel" is from c. 1400, as is that of "consultation, conference," now obsolete except in legalese phrase under advisement. The unetymological -d- is a 16c. scribal overcorrection.
It forms all or part of: advice; advise; belvedere; clairvoyant; deja vu; Druid; eidetic; eidolon; envy; evident; guide; guidon; guise; guy (n.1) "small rope, chain, wire;" Gwendolyn; Hades; history; idea; ideo-; idol; idyll; improvisation; improvise; interview; invidious; kaleidoscope; -oid; penguin; polyhistor; prevision; provide; providence; prudent; purvey; purview; review; revise; Rig Veda; story (n.1) "connected account or narration of some happening;" supervise; survey; twit; unwitting; Veda; vide; view; visa; visage; vision; visit; visor; vista; voyeur; wise (adj.) "learned, sagacious, cunning;" wise (n.) "way of proceeding, manner;" wisdom; wiseacre; wit (n.) "mental capacity;" wit (v.) "to know;" witenagemot; witting; wot.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit veda "I know;" Avestan vaeda "I know;" Greek oida, Doric woida "I know," idein "to see;" Old Irish fis "vision," find "white," i.e. "clearly seen," fiuss "knowledge;" Welsh gwyn, Gaulish vindos, Breton gwenn "white;" Gothic, Old Swedish, Old English witan "to know;" Gothic weitan "to see;" English wise, German wissen "to know;" Lithuanian vysti "to see;" Bulgarian vidya "I see;" Polish widzieć "to see," wiedzieć "to know;" Russian videt' "to see," vest' "news," Old Russian vedat' "to know."
"counsel, advice," Old English ræd "advice, counsel," from Proto-Germanic *redin (source also of Old Saxon rad "advice, counsel, help, advantage," Old Frisian red "council, advice," Dutch raad "advice, counsel," German Rat "advice, counsel," Old Norse rað "advice, consideration, remedy, power; marriage"), from the source of read (v.), which originally meant "to advise, counsel." A very frequent word in Old English and early Middle English, falling from literary use 17c. until revived somewhat in 19th century archaic and poetic diction.
The verb read in the already obsolete sense ' counsel, advise,' was much affected by Spenser, and in the early modern and ME. spelling rede which he used has likewise been much affected by his archaizing imitators; but there is no historical ground for a difference in spelling. [Century Dictionary]
"ask advice of, seek the opinion of as a guide to one's own judgment," 1520s, from French consulter (16c.), from Latin consultare "consult, take the advice of," frequentative of consulere "to take counsel, meet and consider," originally probably "to call together," as in consulere senatum "to gather the senate" (to ask for advice), from Proto-Italic *kom-sel-e-, from *kom- "with, together" (see con-) + *sel-e- "take, gather together," from PIE root *s(e)lh- "to take" (said to be also the source of Middle Welsh dyrllid "to earn," Gothic saljan "to sacrifice," Old Norse selja "to sell, hand over"). Related: Consulted; consulting.
"pertaining to consultation, advisory," 1580s, from Medieval Latin *consultativus, from consultat-, past-participle stem of consultare "consult, take the advice of" (see consult).
Greek goddess personifying prudence, first wife of Zeus, from Greek Mētis, literally "advice, wisdom, counsel; cunning, skill, craft," from PIE root *me- (2) "to measure."