Exoskeleton

[Sarah]

The hardened parts of the external integument of an animal,including hair, feathers, nails, horns, scales, etc.,as well as thearmor of armadillos and many reptiles, and the shells or hardenedintegument of numerous invertebrates; external skeleton;dermoskeleton.

[Sarah]

a hard outer layer that covers, supports, and protects the body of an invertebrate animal such as an insect or crustacean

[Luis Fok]

A rigid external covering for the body in some invertebrate animals, especially arthropods.