Source : Free On-Line Dictionary of Computing

antivirus software
     
         Programs to detect and remove computer {viruses}.  The
        simplest kind scans executable files and {boot blocks} for a
        list of known viruses.  Others are constantly active,
        attempting to detect the actions of general classes of
        viruses.  antivirus software should always include a regular
        update service allowing it to keep up with the latest viruses
        as they are released.
     
        (1998-02-25)