Source : Free On-Line Dictionary of Computing

MUD Object Oriented
     
         (MOO) One of the many {MUD} spin-offs (e.g. {MUSH},
        {MUSE}, and {MUX}) created to diversify the realm of
        interactive text-based gaming.  A MOO is similar to a MUSH in
        that the users themselves can create objects, rooms, and code
        to add to the environment.
     
        The most frequently used {server} {software} for running a MOO
        is {LambdaMOO} but alternatives include {WinMOO
        (http://www-personal.umich.edu/~cunkel/WinMOO/)} and
        {MacGoesMOO
        (http://neon.ci.lexington.ma.us/SpamCentral/scaron/mgm.html)}.
     
        (1999-05-25)