äbˈvenchən noun
( -s )
Etymology: Middle English obvencioun, from Middle French obvention, from Latin obvention-, obventio income, revenue, from Latin obventus (past participle of obvenire to come about, from ob- to, toward + venire to come) + -ion-, -io -ion — more at ob- , come
: something that comes casually (as an incidental advantage or an occasional religious offering)