*we-

also Nirvana, Nirwana, 1836, in Buddhism, "the condition of a Buddha," from Sanskrit nirvana-s "extinction, disappearance" (of the individual soul into the universal), literally "to blow out, a blowing out" ("not transitively, but as a fire ceases to draw" [Ananda Kentish Coomaraswamy, "Hinduism and Buddhism," 1943]; a literal Latinization would be de-spiration), from nis-, nir- "out" + va- "to blow" (from PIE root *we- "to blow"). Figurative sense of "perfect bliss" is from 1895.

late 14c., "emit from a confined space," probably a shortening of aventer "expose oneself to the air" (c. 1300), from Old French eventer "let out, expose to air," from Vulgar Latin *exventare, from Latin ex "out" + ventus "wind" (from PIE *wē-nt-o‑ "blowing," suffixed (participial) form of root *we- "to blow").

Sense of "express freely" first recorded 1590s. Sense of "divulge, publish" (1590s) is behind phrase vent one's spleen (see spleen). Related: Vented; venting.