Source : Webster's Revised Unabridged Dictionary (1913)

Terrapin \Ter"ra*pin\, n. [Probably of American Indian origin.]
   (Zo["o]l.)
   Any one of numerous species of tortoises living in fresh and
   brackish waters. Many of them are valued for food. [Written
   also {terapin}, {terrapen}, {terrapene}, and {turapen}.]

Source : WordNet®

terrapin
     n : any of various edible North American web-footed turtles
         living in fresh or brackish water