An event is a specific action that occurs on or with a certain object. Clicking a button is an event, called the Click event. The Click event in this case occurs on the button object. Other events include the Dbl Click event (for double-clicking) and the On Enter event, which occurs, for example, when a user "enters" a field by clicking it. If you want to run a macro in response to an event, you have to work in the object's property sheet. The property sheet lists all of the events applicable to the object. You can choose the event and then specify the macro that will run when it occurs, or create a new macro in the Macro window.
Assign a Macro to an Event
Create a New Macro for an Event