/ ˈtrɪgə(r); NAmE / noun , verb
■ noun
1.
the part of a gun that you press in order to fire it :
to pull / squeeze the trigger
He kept his finger on the trigger.
2.
trigger (for sth) | trigger (to sth / to do sth) something that is the cause of a particular reaction or development, especially a bad one :
The trigger for the strike was the closure of yet another factory.
3.
the part of a bomb that causes it to explode :
nuclear triggers
■ verb [ vn ]
1.
trigger sth (off) to make sth happen suddenly
SYN set off :
Nuts can trigger off a violent allergic reaction.
2.
to cause a device to start functioning
SYN set off :
to trigger an alarm
••
WORD ORIGIN
early 17th cent.: from dialect tricker , from Dutch trekker , from trekken to pull.