Origin: 1200–50; Middle English aventure < Anglo-French, Old French < Vulgar Latin *adventūra what must happen, feminine (orig. neuter plural) of Latin adventūrus future participle of advenīre to arrive; ad-ad- replacing a-a-5. See advent, -ure
early 13c., auenture "chance, fortune, luck," from O.Fr. auenture, from L. adventura (res) "(a thing) about to happen," from adventurus, future participle of advenire "to come about," from ad- "to" + venire "to come" (see venue). Original meaning was "to arrive," in Latin,
but in M.E. it took a turn through "risk/danger" (a trial of one's chances), and "perilous undertaking" (early 14c.), and thence to "a novel or exciting incident" (1570). The -d- was restored 15c.-16c. Venture (q.v.) is a 15c. variant.