■ noun
1》 a device that releases a spring or catch and so sets off a mechanism, especially in order to fire a gun.
2》 an event that causes something to happen.
■ verb
1》 cause (a device) to function.
2》 (also ~ something off ) cause to happen or exist.
Derivatives
~ed adjective
Origin
C17: from dialect tricker , from Du. trekker , from trekken 'to pull'.