Source : Webster's Revised Unabridged Dictionary (1913)

Sea otter \Sea" ot"ter\ (Zo["o]l.)
   An aquatic carnivore ({Enhydris lutris, or marina}) found in
   the North Pacific Ocean. Its fur is highly valued, especially
   by the Chinese. It is allied to the common otter, but is
   larger, with feet more decidedly webbed.

   {Sea-otter's cabbage} (Bot.), a gigantic kelp of the Pacific
      Ocean ({Nereocystis Lutkeana}). See {Nereocystis}.

Otter \Ot"ter\, n. [OE. oter, AS. otor; akin to D. & G. otter,
   Icel. otr, Dan. odder, Sw. utter, Lith. udra, Russ, vuidra,
   Gr. "y`dra water serpent, hydra, Skr. udra otter, and also to
   E. water. [root]137, 215. See {Water}, and cf. {Hydra}.]
   1. (Zo["o]l.) Any carnivorous animal of the genus {Lutra},
      and related genera. Several species are described. They
      have large, flattish heads, short ears, and webbed toes.
      They are aquatic, and feed on fish. Their fur is soft and
      valuable. The common otter of Europe is {Lutra vulgaris};
      the American otter is {L. Canadensis}; other species
      inhabit South America and Asia.

   2. (Zo["o]l.) The larva of the ghost moth. It is very
      injurious to hop vines.

   {Otter hound}, {Otter dog} (Zo["o]l.), a small breed of
      hounds, used in England for hunting otters.

   {Otter sheep}. See {Ancon sheep}, under {Ancon}.

   {Otter shell} (Zo["o]l.), very large bivalve mollusk
      ({Schizoth[ae]rus Nuttallii}) found on the northwest coast
      of America. It is excellent food, and is extensively used
      by the Indians.

   {Sea otter}. (Zo["o]l.) See in the Vocabulary.

Source : WordNet®

sea otter
     n : large marine otter of northern Pacific coasts having very
         thick dark brown fur [syn: {Enhydra lutris}]