The Collaborative International Dictionary of English v.0.48:

Meerschaum \Meer"schaum\ (m[=e]r"sh[add]m; 277), n. [G., lit.,
   sea foam; meer sea + schaum foam; but it perh. is a
   corruption of the Tartaric name myrsen. Cf. Mere a lake,
   and Scum.]
   1. (Min.) A fine white claylike mineral, soft, and light
      enough when in dry masses to float in water. It is a
      hydrous silicate of magnesia, and is obtained chiefly in
      Asia Minor. It is manufacturd into tobacco pipes, cigar
      holders, etc. Also called sepiolite.
      [1913 Webster]

   2. A tobacco pipe made of this mineral; a meerschaum pipe.
      [1913 Webster]

WordNet (r) 3.0 (2006):

meerschaum
    n 1: a white clayey mineral [syn: meerschaum, sepiolite]
    2: a pipe having a bowl made of meerschaum

Moby Thesaurus II by Grady Ward, 1.0:

60 Moby Thesaurus words for "meerschaum":
   Missouri meerschaum, accommodate, act between, adjust, arbitrate,
   bargain, briar, briar pipe, calean, calumet, churchwarden, clay,
   compose, compound, compromise, cop out, corncob, corncob pipe,
   duck responsibility, evade responsibility, give and take, give way,
   go between, go fifty-fifty, hookah, hubble-bubble, intercede,
   intermediate, interpose, intervene, judge, make a deal,
   make an adjustment, make concessions, make terms, mediate,
   meet halfway, moderate, nargileh, negotiate, peace pipe, pipe,
   pipe cleaner, pipe rack, play politics, reach a compromise,
   referee, represent, settle, split the difference, step in,
   strike a balance, strike a bargain, surrender, take the mean,
   tobacco pipe, tobacco pouch, treat with, umpire, yield



The Devil's Dictionary (1881-1906):

MEERSCHAUM, n.  (Literally, seafoam, and by many erroneously supposed
to be made of it.)  A fine white clay, which for convenience in
coloring it brown is made into tobacco pipes and smoked by the workmen
engaged in that industry.  The purpose of coloring it has not been
disclosed by the manufacturers.

    There was a youth (you've heard before,
        This woeful tale, may be),
    Who bought a meerschaum pipe and swore
        That color it would he!

    He shut himself from the world away,
        Nor any soul he saw.
    He smoke by night, he smoked by day,
        As hard as he could draw.

    His dog died moaning in the wrath
        Of winds that blew aloof;
    The weeds were in the gravel path,
        The owl was on the roof.

    "He's gone afar, he'll come no more,"
        The neighbors sadly say.
    And so they batter in the door
        To take his goods away.

    Dead, pipe in mouth, the youngster lay,
        Nut-brown in face and limb.
    "That pipe's a lovely white," they say,
        "But it has colored him!"

    The moral there's small need to sing --
        'Tis plain as day to you:
    Don't play your game on any thing
        That is a gamester too.
                                                      Martin Bulstrode