n. 25B6; verb
the incident triggered an acrimonious debate : PRECIPITATE, prompt, trigger off, set off, spark (off), touch off, provoke, stir up; cause, give rise to, lead to, set in motion, occasion, bring about, generate, engender, begin, start, initiate; poetic/literary enkindle.
burglars triggered the alarm : ACTIVATE, set off, set going, trip.