The Collaborative International Dictionary of English v.0.48:

Sea otter \Sea" ot"ter\ (Zool.)
   An aquatic carnivore (Enhydris lutris syn. Enhydris
   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.
   [1913 Webster]

   Sea-otter's cabbage (Bot.), a gigantic kelp of the Pacific
      Ocean (Nereocystis Lutkeana). See Nereocystis.
      [1913 Webster]