The Free On-line Dictionary of Computing (30 December 2018):

event-driven

    A kind of program, such as a graphical user
   interface, with a main loop which just waits for events to
   occur.  Each event has an associated handler which is passed
   the details of the event, e.g. mouse button 3 pressed at
   position (355, 990).

   For example, X window system and most Visual Basic
   application programs are event-driven.

   See also callback.

   (2000-02-09)