window system windowing windowing system Software which allows a {workstation}'s screen to be divided into rectangular areas which act like a separate input/output devices under the control of different {application} programs. This gives the user the ability to see the output of several processes at once and to choose which one will receive input by selecting its window, usually by pointing at it with a {mouse}. Examples are the {X Window System}, and proprietary systems on the {Macintosh} and {NeXT}, {NeWS} on {Suns} and {RISC OS} on the {Archimedes}. See also {WIMP}.