Source : Free On-Line Dictionary of Computing

twm
     
        Tab Window Manager.
     
        A {window manager} for the {X Window System}.  Twm provides
        {titlebar}s, shaped windows, several forms of icon management,
        user-defined macro functions, {click-to-type} and
        pointer-driven {keyboard focus}, and user-specified key and
        pointer button bindings.  It can be extensively configured by
        a startup file.
     
        Twm was written by Tom LaStrange, {Solbourne Computer}; Jim
        Fulton, MIT {X Consortium}; Steve Pitschke, {Stardent
        Computer}; Keith Packard, MIT X Consortium; Dave Sternlicht,
        MIT X Consortium; Dave Payne, {Apple Computer}.
     
        An extended version, {vtwm}, provides a {virtual desktop}.
     
        [Why "Tab"?]
     
        (1995-02-14)