D defs.my
Entry 2 senses Webster, 1913

Trigger

/trĭg'-ẽr/ · Trig·ger · IPA /ˈtɹɪɡɚ/
01 n. A catch to hold the wheel of a carriage on a declivity.
  1. 1.
    A catch to hold the wheel of a carriage on a declivity.
  2. 2.
    A piece, as a lever, which is connected with a catch or detent as a means of releasing it; especially (Firearms), the part of a lock which is moved by the finger to release the cock and discharge the piece.(Mech.)
Phrases & compounds
Trigger fish — a large plectognath fish (Balistes Carolinensis or Balistes capriscus) common on the southern coast of the United States, and valued as a food fish in some localities. Its rough skin is used for scouring and polishing in the place of sandpaper. Called also leather jacket, and turbot.