early 14c., raven, "to show signs of madness or delirium, to rage in speech," from Old French raver, variant of resver "to dream; wander here and there, prowl; behave madly, be crazy," a word of unknown origin (compare reverie). An identical (in form) verb meaning "to wander, stray, rove" dates from late 14c. in Scottish and northern dialect, and is probably from a Scandinavian word (such as Old Norse rafa). Sense of "talk about (something or someone) enthusiastically or immoderately" is recorded by 1704. Related: Raved; raving.
1590s, "frenzy, great excitement," from rave (v.). Meaning "temporary popular enthusiasm" is from 1902; that of "highly flattering review" is by 1926 (when it was noted as a Variety magazine word). By 1960 as "rowdy party;" rave-up was British slang for "wild party" from 1940; the specific sense of "mass party with loud, fast electronic music and often psychedelic drugs" is by 1989.