Source : Free On-Line Dictionary of Computing

ABEND
     
         /o'bend/, /*-bend'/ ABnormal END.  Abnormal
        termination (of {software}); {crash}; {lossage}.  Derives from
        an error message on the {IBM 360}; used jokingly by hackers
        but seriously mainly by {code grinder}s.  Usually capitalised,
        but may appear as "abend".  Hackers will try to persuade you
        that ABEND is called "abend" because it is what system
        operators do to the computer late on Friday when they want to
        call it a day, and hence is from the German "Abend" =
        "Evening".
     
        [{Jargon File}]
     
        (1994-11-08)