mud
     n 1: water soaked soil; soft wet earth [syn: {clay}]
     2: slanderous remarks or charges
     v 1: soil with mud, muck, or mire; "The child mucked up his shirt
          while playing ball in the garden" [syn: {mire}, {muck},
          {muck up}]
     2: plaster with mud
     [also: {mudding}, {mudded}]
Source: WordNet® 2.0

MUD /muhd/ n. [acronym, Multi-User Dungeon; alt. Multi-User Dimension]
   1. A class of {virtual reality} experiments accessible via the Internet.
   These are real-time chat forums with structure; they have multiple
   `locations' like an adventure game, and may include combat, traps,
   puzzles, magic, a simple economic system, and the capability for
   characters to build more structure onto the database that represents the
   existing world. 2. vi. To play a MUD. The acronym MUD is often
   lowercased and/or verbed; thus, one may speak of `going mudding', etc.

   Historically, MUDs (and their more recent progeny with names of MU-
   form) derive from a hack by Richard Bartle and Roy Trubshaw on the
   University of Essex's DEC-10 in the early 1980s; descendants of that
   game still exist today and are sometimes generically called BartleMUDs.
   There is a widespread myth (repeated, unfortunately, by earlier versions
   of this lexicon) that the name MUD was trademarked to the commercial MUD
   run by Bartle on British Telecom (the motto: "You haven't _lived_ 'til
   you've _died_ on MUD!"); however, this is false -- Richard Bartle
   explicitly placed `MUD' in the public domain in 1985. BT was upset at
   this, as they had already printed trademark claims on some maps and
   posters, which were released and created the myth.

   Students on the European academic networks quickly improved on the MUD
   concept, spawning several new MUDs (VAXMUD, AberMUD, LPMUD). Many of
   these had associated bulletin-board systems for social interaction.
   Because these had an image as `research' they often survived
   administrative hostility to BBSs in general. This, together with the
   fact that Usenet feeds were often spotty and difficult to get in the
   U.K., made the MUDs major foci of hackish social interaction there.

   AberMUD and other variants crossed the Atlantic around 1988 and
   quickly gained popularity in the U.S.; they became nuclei for large
   hacker communities with only loose ties to traditional hackerdom (some
   observers see parallels with the growth of Usenet in the early 1980s).
   The second wave of MUDs (TinyMUD and variants) tended to emphasize
   social interaction, puzzles, and cooperative world-building as opposed
   to combat and competition (in writing, these social MUDs are sometimes
   referred to as `MU*', with `MUD' implicitly reserved for the more
   game-oriented ones). By 1991, over 50% of MUD sites were of a third
   major variety, LPMUD, which synthesizes the combat/puzzle aspects of
   AberMUD and older systems with the extensibility of TinyMud. In 1996 the
   cutting edge of the technology is Pavel Curtis's MOO, even more
   extensible using a built-in object-oriented language. The trend toward
   greater programmability and flexibility will doubtless continue.

   The state of the art in MUD design is still moving very rapidly, with
   new simulation designs appearing (seemingly) every month. Around 1991
   there was an unsuccessful movement to deprecate the term {MUD} itself,
   as newer designs exhibit an exploding variety of names corresponding to
   the different simulation styles being explored. It survived. See also
   {bonk/oif}, {FOD}, {link-dead}, {mudhead}, {talk mode}.


Source: The Jargon File

MUD
     Multi-User Dungeon (MUD)
     
     
Source: Virtual Entity of Relevant Acronyms