the part of a gun that you pull with your finger to fire it

〔枪的〕扳机:

He took aim and squeezed the trigger.

他瞄准目标，扣动了扳机。

be the trigger (point) (for sth), to be the thing that quickly causes a serious problem

成为引发（某事）的因素:

The hijacking became a trigger point for military action.

这次劫持事件成了引发军事行动的导火线。

to make something happen very quickly, especially a series of events

引发，激发〔尤指一系列事件〕:

The assassination triggered off a wave of rioting.

这次暗杀事件引发了一波骚乱。

Certain forms of mental illness can be triggered by food allergies.

某些精神疾病会因为食物过敏而被引发。

His action triggered a massive response from the government.

他的行动激起了来自政府的极大反响。

to make something such as a bomb or electrical system start to operate

使爆炸; 启动，引发:

The burglars fled after triggering the alarm .

入室窃贼触动报警器后就逃跑了。