Trigger point,

Definition of Trigger point:

1. Change in an attribute, condition, factor, parameter, or value that represents crossing a threshold and actuates or initiates a mechanism or reaction that may lead to a radically different state of affairs.

2. A particular circumstance or situation that causes an event to occur.

How to use Trigger point in a sentence?

1. The armys refusal to withdraw from the territory was the trigger point for military action.