trigger

1 of 2

noun

trig·​ger ˈtri-gər 

1

a

: a piece (such as a lever) connected with a catch or detent as a means of releasing it

especially : the part of the action moved by the finger to fire a gun

b

: a similar movable part by which a mechanism is actuated

trigger of a spray gun

2

: something that acts like a mechanical trigger in initiating a process or reaction

trigger

2 of 2

verb

triggered; triggering ˈtri-g(ə-)riŋ 

transitive verb

1

a

: to release or activate by means of a trigger

especially : to fire by pulling a mechanical trigger

trigger a rifle

b

: to cause the explosion of

trigger a missile

2

: to initiate, actuate, or set off by a trigger

an indiscreet remark that triggered a fight

a stimulus that triggered a reflex

3

: to cause an intense and usually negative emotional reaction in (someone)

Water had a way of triggering my brother and making ordinary, everyday weather take a frightening turn for the worse.

—Ingrid Law

intransitive verb

: to release a mechanical trigger

Synonyms of trigger

Verb

• activate
• spark
• drive

Examples of trigger in a Sentence

Verb

Smoke triggered the fire alarm.

The timer was set to trigger the bomb in exactly one hour.

His remarks triggered a public outcry.

Certain foods trigger his headaches.

The power outage was triggered by heavy rains.

Recent Examples on the Web

Noun

Stepping into a room that hot triggers an immediate stress reaction, activating the sympathetic arm of the nervous system, the fight-or-flight response. —Will Stone, NPR, 6 Mar. 2026

Several aspects of Earth's climate and ecological systems changed in the late 1990s, with a possible trigger by a major El Nino event in 1997-98, said Gerald Meehl, a climate scientist at the National Center for Atmospheric Research who wasn't part of the study. —ABC News, 6 Mar. 2026

Verb

Penn State researchers have proposed that the fury of a lightning bolt can be tamed, shrunk, and triggered on a lab bench inside a piece of acrylic no bigger than a deck of cards. —Mrigakshi Dixit, Interesting Engineering, 6 Mar. 2026

While this week’s increase was relatively small, financial analysts warn that a prolonged conflict in the Middle East could trigger a broader bond sell-off. —Alexandra Banner, CNN Money, 6 Mar. 2026

Word History

Etymology

Noun

alteration of earlier tricker, from Dutch trekker, from Middle Dutch trecker one that pulls, from trecken to pull — more at trek

First Known Use

Noun

1621, in the meaning defined at sense 1a

Verb

1902, in the meaning defined at transitive sense 1a

Phrases Containing trigger

• hair trigger
• pull the trigger
• quick on the trigger
• trigger ban
• trigger-happy
• trigger law
• trigger point

Rhymes for trigger

• bigger
• digger
• jigger
• rigger
• rigor
• vigor
• gravedigger
• obligor
• outrigger

Kids Definition

trigger

1 of 2 noun

trig·​ger ˈtrig-ər 

1

: a movable lever that activates a device when it is squeezed

especially : the part of the lock of a firearm that releases the hammer and so fires the gun

2

: something that causes something else to happen

trigger adjective

triggered

-ərd 

adjective

trigger

2 of 2 verb

triggered; triggering -(ə-)riŋ 

1

: to fire by pulling a trigger

2

: to begin, stir up, or set in motion as if by pulling a trigger

the remark that triggered the laughter