An event within the processes of healthcare which, when recorded or recognized by a healthcare information system, creates the need for an information flow to one or more other healthcare information systems. The information may flow may be implemented by one or more interactions. Trigger events are closely associated with state transitions and leaf level use cases.

A trigger event is a finite event with start and end time that defines when a trigger started and stopped a screen recording. Whereas a recording rule describes the conditions of recording, a trigger event is the instances of when it happened. A trigger rule can result in many trigger events.

An event (such as a message arriving on a queue) that causes a queue manager to create a trigger message on an initiation queue.

Event that causes a virus to activate itself and unleash its payload. This can be a particular date i.e. April Fool's Day, Michelangelo's birthday or perhaps a counter, incremented each time the computer boots, reaching a certain value.