What is a “trigger” in Tag Manager?

A trigger in Google Tag Manager (GTM) is a condition that, when met, causes a tag to fire. For example, a "Page View" trigger fires a tag when a specific page loads, or a "Click" trigger fires a tag when a user clicks a particular element. Triggers define when a tag should execute, ensuring data is collected or actions are performed at the appropriate moment. The incorrect options describe other GTM functionalities or misrepresent the role of a trigger: "A trigger determines which events fire on your website" is incorrect; events happen independently, and triggers respond to them. "A trigger instantiates the data layer" is incorrect; the data layer is typically initialized by code on the website itself, not by a trigger. "A trigger publishes a tag to your website" is incorrect; publishing is the final step of deploying a GTM container, not the function of a trigger.