1570s, "the consequence of anything" (as in in the event that); 1580s, "that which happens;" from French event, from Latin eventus "occurrence, accident, event, fortune, fate, lot, issue," from past participle stem of evenire "to come out, happen, result," from assimilated form of ex- "out" (see ex-) + venire "to come" (from a suffixed form of PIE root *gwa- "to go, come"). Meaning "a contest or single proceeding in a public sport" is from 1865. Events as "the course of events" is attested from 1842. Event horizon in astrophysics is from 1969.
*gwā-, also *gwem-, Proto-Indo-European root meaning "to go, come."
It forms all or part of: acrobat; adiabatic; advent; adventitious; adventure; amphisbaena; anabasis; avenue; base (n.) "bottom of anything;" basis; become; circumvent; come; contravene; convene; convenient; convent; conventicle; convention; coven; covenant; diabetes; ecbatic; event; eventual; hyperbaton; hypnobate; intervene; intervenient; intervention; invent; invention; inventory; juggernaut; katabatic; misadventure; parvenu; prevenient; prevent; provenance; provenience; revenant; revenue; souvenir; subvention; supervene; venire; venue; welcome.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit gamati "he goes," Avestan jamaiti "goes," Tocharian kakmu "come," Lithuanian gemu, gimti "to be born," Greek bainein "to go, walk, step," Latin venire "to come," Old English cuman "come, approach," German kommen, Gothic qiman.
also rain-check, rain check, "ticket given to a spectator at an outdoor event for admission at a later date, or refund, should the event be interrupted by rain," 1884; see rain (n.) + check (n.1). Originally of tickets to rained-out baseball games.
in rhetoric, "comparison, metaphor," according to Century Dictionary, "especially a formal simile, as in poetry or poetic prose, taken from a present or imagined object or event: distinguished from a paradigm, or comparison with a real past event," 1580s, from Greek parabolē "comparison" (see parable).
as an annual ecological awareness event on April 22, from 1970; the idea for it and the name date from 1969.