trigger

noun

1. A finger-operated lever used to fire a gun.

   “Just pull the trigger.”

   “[W]e pull'd aſide the Tricker, and obſerv'd, that according to our expectation the force of the Spring of the Lock vvas not ſenſibly abated by the abſence of the Air.”

2. A similar device used to activate any mechanism.
3. An event that initiates others, or incites a response.

   “Sleeping in an unfamiliar room can be a trigger for sleepwalking.”

4. An event that initiates others, or incites a response.
5. A concept or image that upsets somebody by sparking a negative emotional response.

   “emotional trigger”

   “I can't watch that violent film. Blood is one of my triggers.”

6. An event, experience or other stimulus that initiates a traumatic memory or a strong reaction in a person.
7. An electronic transducer allowing a drum, cymbal, etc. to control an electronic drum unit or similar device.
8. A device that manually lengthens (or sometimes shortens) the slide or tubing of a brass instrument, allowing the pitch range to be altered while playing.
9. A pulse in an electronic circuit that initiates some component.
10. An SQL procedure that may be initiated when a record is inserted, updated or deleted; typically used to maintain referential integrity.
11. (archaic)A catch to hold the wheel of a carriage on a declivity.
12. An argument whose semantic role determines the choice of a verbal affix, in certain Austronesian languages.

verb

1. (transitive)To fire (a weapon).

   “A U235 bomb would therefore need to incorporate a gun weighing ten tons. Then there was the question of initiating or triggering the bomb.”

2. (transitive)To cause, to precipitate, to bring (something) about in response or as a result.

   “The controversial article triggered a deluge of angry letters from readers.”

   “The accident followed torrential early morning rain that triggered widespread flooding across Scotland's tracks, including south of Carmont.”

3. (figuratively, transitive)To spark a response, especially a negative emotional response, in (a person).

   “This story contains a rape scene and may be triggering for rape victims.”

   “People get triggered simply by seeing a Trump.”

   “I encountered a forum user who didn't agree with me, so I wrote some comments with my political slogans to trigger that clueless kiddo.”

4. (especially, intransitive)To activate; to become active.

   “Sodium nitrite (750 ppm) was added after the alarm triggered at three hours, and corrosion did not occur for over eight hours.”

adj

1. (comparative, form-of)comparative form of trig: more trig