Source : Webster's Revised Unabridged Dictionary (1913)

Sea turtle \Sea" tur"tle\ (Zo["o]l.)
   (a) Any one of several very large species of chelonians
       having the feet converted into paddles, as the green
       turtle, hawkbill, loggerhead, and leatherback. They
       inhabit all warm seas.
   (b) The sea pigeon, or guillemot.

Source : WordNet®

sea turtle
     n : any of various large turtles with limbs modified into
         flippers; widely distributed in warm seas [syn: {marine
         turtle}]