Source : Webster's Revised Unabridged Dictionary (1913)

Turtle \Tur"tle\, n. [AS. turtle, L. turtur; probably of
   imitative origin. Cf. {Turtle} the sea tortoise.] (Zo["o]l.)
   The turtledove.

Turtle \Tur"tle\, n. [Probably the same word as the word
   preceding, and substituted (probably by sailors) for the
   Spanish or Portuguese name; cf. Sp. tortuga tortoise, turtle,
   Pg. tartaruga, also F. tortue, and E. tortoise.]

Source : WordNet®

turtle
     n : any of various aquatic and land reptiles having a bony shell
         and flipper-like limbs for swimming

turtle
     v 1: overturn accidentally; "Don't rock the boat or it will
          capsize!" [syn: {capsize}, {turn turtle}]
     2: hunt for turtles, especially as an occupation