trigger

The definition of a trigger is the mechanism on a gun that makes it shoot a bullet or anything that starts a series of events.

(noun)

An example of trigger is what a cop presses to fire his gun.
An example of trigger is a hostile confrontation that causes a series of bad memories with the person.

Trigger is defined as to fire a gun or to start a series of events or emotions.

(verb)

An example of trigger is to shoot a rifle while hunting.
An example of trigger is to start crying at a movie, thereby causing many other people in the theater to begin weeping.

See trigger in Webster's New World College Dictionary

noun

a small lever or part which when pulled or pressed releases a catch, spring, etc.
in firearms, a small lever pressed back by the finger to activate the firing mechanism
an act, impulse, etc. that initiates an action, series of events, etc.

Origin: earlier tricker < Du trekker < trekken, to draw, pull: see trek

transitive verb

See trigger in American Heritage Dictionary 4

noun

a. The lever pressed by the finger to discharge a firearm.
b. A similar device used to release or activate a mechanism.
An event that precipitates other events.
Electronics A pulse or circuit that initiates the action of another component.

transitive verb trig·gered, trig·ger·ing, trig·gers