Source : Free On-Line Dictionary of Computing

condition out
     
        To prevent a section of code from being compiled by
        surrounding it with a {conditional compilation} directive
        whose condition is always false.  The {canonical} examples of
        these directives are "#if 0" (or "#ifdef notdef", though some
        find the latter bletcherous) and "#endif" in {C}.  Compare
        {comment out}.
     
        [{Jargon File}]
     
        (1994-11-30)