trigger: Meaning and Definition of

trig•ger

1. a small projecting tongue in a firearm that, when pressed by the finger, actuates the mechanism that discharges the weapon.
2. a device, as a lever, the pulling or pressing of which releases a detent or spring.
3. anything, as an act or event, that serves as a stimulus and initiates or precipitates a reaction or series of reactions.
4. triggerman.
5. quick to act or respond; impetuous; alert.

1. to initiate or precipitate (a chain of events, scientific reaction, psychological process, etc.): Their small protest triggered a mass demonstration.
2. to fire or explode (a gun, missile, etc.) by pulling a trigger or releasing a triggering device: He accidentally triggered his rifle.

1. to release a trigger.
2. to become active; activate.