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1.                 From The Free On-line Dictionary of Computing (19 January 2023):
                   
   
   
                   
                     
   MUD Object Oriented
   MOO
      <games> (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)