The term carapace refers to a dorsal section of an exoskeleton or shell, in a number of animal groups.

Crustaceans

In crustaceans, the carapace is a part of the exoskeleton that covers the cephalothorax. It is particularly well developed in lobsters and crabs. It functions as a protective cover of the cephalothorax.

Tortoises

The carapace is the dorsal, convex part of the shell structure of the tortoise, consisting of an external layer of horny material, divided into large plates known as scutes, which overlie a layer of interlocking bones. This construction allows for a sturdy tortoise.

The plastron makes up the other half of the tortoise's shell. All tortoises from sea turtles to box (or painted) turtles and desert tortoises can be distinguished by their species-specific arrangment of scutes.