v.intr. (often foll. by between, in) 1 occur in time between events. 2 interfere; come between so as to prevent or modify the result or course of events. 3 be situated between things. 4 come in as an extraneous factor or thing. 5 Law interpose in a lawsuit as a third party. intervener n. intervenient adj. intervenor n.
[ L intervenire (as INTER-, venire come) ]