in·ter·vene / ˌintərˈvēn/ • v. [intr.] 1. come between so as to prevent or alter a result or course of events: he acted outside his authority when he intervened in the dispute | their forces intervened to halt the attack. ∎ (of an event or circumstance) occur as a delay or obstacle to something being done: Christmas intervened, and the investigation was suspended. ∎ interrupt verbally: [with direct speech] “It's true!” he intervened. ∎ Law interpose in a lawsuit as a third party.2. [usu. as adj.] (intervening) occur in time between events: to occupy the intervening months, she took a job in a hospital. ∎ be situated between things: they heard the sound of distant gunfire, muffled by the intervening trees.DERIVATIVES: in·ter·ven·er n.in·ter·ven·ient / -ˈvēnyənt/ adj.in·ter·ve·nor / -ˈvēnər/ n.