Source : Webster's Revised Unabridged Dictionary (1913)

Sea snail \Sea" snail`\ (Zo["o]l.)
   (a) A small fish of the genus {Liparis}, having a ventral
       sucker. It lives among stones and seaweeds.
   (b) Any small creeping marine gastropod, as the species of
       Littorina, Natica, etc.

Source : WordNet®

sea snail
     n : small tadpole-shaped cold-water fishes with pelvic fins
         forming a sucker; related to lumpfish [syn: {snailfish},
         {seasnail}, {Liparis liparis}]