Source : Free On-Line Dictionary of Computing

exception handler
     
        Special code which is called when an {exception} occurs during
        the execution of a program.  If the programmer does not
        provide a handler for a given exception, a built-in system
        exception handler will usually be called resulting in abortion
        of the program run and some kind of error indication being
        returned to the user.
     
        Examples of exception handler mechanisms are {Unix}'s signal
        calls and {Lisp}'s {catch} and {throw}.
     
        (1994-10-31)