An event is an instantaneous occurrence that can trigger a state transition in the class that receives it. Because events are objects, they can carry information about the occurrence, such as the time at which it happened. The browser icon for an event is a lightning bolt.
The following figure shows the Features window for an event.

A triggered operation can trigger a state transition in a statechart, just like an event. The body of the triggered operation is executed as a result of the transition being taken. The browser icon for a triggered operation is a green operation box overlaid with a lightning bolt.
By default, operations are primitive operations. Primitive operations are those operations whose bodies you define yourself instead of letting Rational Rhapsody generate them for you from a statechart.