Trigger

Trigger skills

Tooltip

Many effects can cause a Skill to Trigger. A Triggered Skill occurs immediately, without an attack or cast time, and usually targets the cause of the trigger. Triggering a Skill does not count as using it.

If multiple methods of Triggering a skill attempt to apply to the same skill, that skill will be disabled.

Trigger is a skill behavior that causes a skill's effect to occur during certain conditions, instantly without the need of manually casting socketed skills.

Right now one of the confirmed ways to trigger other gems is to use a meta spell like Cast on Minion Death.