Source : Webster's Revised Unabridged Dictionary (1913)

Carapace \Car"a*pace\ (k[a^]r"[.a]*p[=a]s), n. [F.] (Zo["o]l.)
   The thick shell or shield which covers the back of the
   tortoise, or turtle, the crab, and other crustaceous animals.

Source : WordNet®

carapace
     n : hard outer covering or case of certain organisms such as
         arthropods and turtles [syn: {shell}, {cuticle}]