definition of
trigger

[1] #1 trigger n. [gun trigger] lever that activates the firing mechanism of a gun. wn

[2] #2 trigger v. [trip, actuate, activate, set off, spark off, spark, trigger off, touch off] put in motion or move to act; "trigger a reaction"; "actuate the circuits". wn

[3] #3 trigger v. release or pull the trigger on; "Trigger a gun". wn

[4] #4 trigger n. a device that activates or releases or causes something to happen. wn

[5] #5 trigger n. [induction, initiation] an act that sets in motion some course of events. wn