The Collaborative International Dictionary of English v.0.48:

Mud \Mud\ (m[u^]d), n. [Akin to LG. mudde, D. modder, G. moder
   mold, OSw. modd mud, Sw. modder mother, Dan. mudder mud. Cf.
   Mother a scum on liquors.]
   Earth and water mixed so as to be soft and adhesive.
   [1913 Webster]

   Mud bass (Zool.), a fresh-water fish (Acantharchum
      pomotis or Acantharchus pomotis) of the Eastern United
      States. It produces a deep grunting note.

   Mud bath, an immersion of the body, or some part of it, in
      mud charged with medicinal agents, as a remedy for
      disease.

   Mud boat, a large flatboat used in dredging.

   Mud cat. See mud cat in the vocabulary.

   Mud crab (Zool.), any one of several American marine crabs
      of the genus Panopeus.

   Mud dab (Zool.), the winter flounder. See Flounder, and
      Dab.

   Mud dauber (Zool.), a mud wasp; the mud-dauber.

   Mud devil (Zool.), the fellbender.

   Mud drum (Steam Boilers), a drum beneath a boiler, into
      which sediment and mud in the water can settle for
      removal.

   Mud eel (Zool.), a long, slender, aquatic amphibian (Siren
      lacertina), found in the Southern United States. It has
      persistent external gills and only the anterior pair of
      legs. See Siren.

   Mud frog (Zool.), a European frog (Pelobates fuscus).

   Mud hen. (Zool.)
   (a) The American coot (Fulica Americana).
   (b) The clapper rail.

   Mud lark, a person who cleans sewers, or delves in mud.
      [Slang]

   Mud minnow (Zool.), any small American fresh-water fish of
      the genus Umbra, as Umbra limi. The genus is allied to
      the pickerels.

   Mud plug, a plug for stopping the mudhole of a boiler.

   Mud puppy (Zool.), the menobranchus.

   Mud scow, a heavy scow, used in dredging; a mud boat.
      [U.S.]

   Mud turtle, Mud tortoise (Zool.), any one of numerous
      species of fresh-water tortoises of the United States.

   Mud wasp (Zool.), any one of numerous species of
      hymenopterous insects belonging to Pepaeus, and allied
      genera, which construct groups of mud cells, attached,
      side by side, to stones or to the woodwork of buildings,
      etc. The female places an egg in each cell, together with
      spiders or other insects, paralyzed by a sting, to serve
      as food for the larva. Called also mud dauber.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mud \Mud\, v. t.
   1. To bury in mud. [R.] --Shak.
      [1913 Webster]

   2. To make muddy or turbid. --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

mud
    n 1: water soaked soil; soft wet earth [syn: mud, 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, mud, muck up]
    2: plaster with mud

Moby Thesaurus II by Grady Ward, 1.0:

59 Moby Thesaurus words for "mud":
   baygall, bog, bottom, bottomland, bottoms, buffalo wallow, clay,
   dirt, dust, everglade, fen, fenland, glade, grime, gumbo,
   hog wallow, holm, marais, marish, marsh, marshland, meadow, mere,
   mire, moor, moorland, morass, moss, muck, mud flat, muddle, muddy,
   ooze, peat bog, quagmire, quicksand, rile, salt marsh, slime, slip,
   slob, slob land, slop, slosh, slough, sludge, slush, smut, soot,
   sough, squash, sump, swale, swamp, swampland, swill, taiga, wallow,
   wash



V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

MUD
       Multi-User Dungeon (MUD)


The Jargon File (version 4.4.7, 29 Dec 2003):

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.


The Free On-line Dictionary of Computing (30 December 2018):

MUD

    Multi-User Dimension or "Multi-User Domain".
   Originally "Multi-User Dungeon".

   [Jargon File]

   (1995-04-16)