trigger

1. (n) (firearms) A finger-operated lever used to fire a gun. 2. (n) An event that initiates others, or incites a response. 3. (n) A similar device used to activate any mechanism. 4. (v) (transitive) To cause, to precipitate, to bring (something) about in response or as a result. 5. (v) (transitive, figurative) To spark a response, especially a negative emotional response, in (a person). 6. (n) (psychology) An event, experience or other stimulus that initiates a traumatic memory or a strong reaction in a person. 7. (n) A concept or image that upsets somebody by sparking a negative emotional response. 8. (v) (transitive) To fire (a weapon). 9. (v) (intransitive, especially electronics) To activate; to become active. 10. (n) (electronics) A pulse in an electronic circuit that initiates some component. 11. (n) (databases) An SQL procedure that may be initiated when a record is inserted, updated or deleted; typically used to maintain referential integrity. 12. (n) (music) An electronic transducer allowing a drum, cymbal, etc. to control an electronic drum unit or similar device. 13. (n) (music) 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. 14. (n) (grammar) An argument whose semantic role determines the choice of a verbal affix, in certain Austronesian languages. 15. (n) (archaic) A catch to hold the wheel of a carriage on a declivity.