The Collaborative International Dictionary of English v.0.48:

Sculpin \Scul"pin\, n. [Written also skulpin.] (Zool.)
   (a) Any one of numerous species of marine cottoid fishes of
       the genus Cottus, or Acanthocottus, having a large
       head armed with several sharp spines, and a broad mouth.
       They are generally mottled with yellow, brown, and black.
       Several species are found on the Atlantic coasts of
       Europe and America.
   (b) A large cottoid market fish of California
       (Scorpaenichthys marmoratus); -- called also bighead,
       cabezon, scorpion, salpa.
   (c) The dragonet, or yellow sculpin, of Europe (Callionymus
       lyra).
       [1913 Webster]

   Note: The name is also applied to other related California
         species.
         [1913 Webster]

   Deep-water sculpin, the sea raven.
      [1913 Webster]

WordNet (r) 3.0 (2006):

sculpin
    n 1: any of numerous spiny large-headed usually scaleless
         scorpaenoid fishes with broad mouths