exoskeleton ex·o·skel·e·ton (ěk'sō-skěl'ĭ-tn)
All hard parts, such as hair, teeth, and nails, that develop from the ectoderm or mesoderm in vertebrates.
A hard outer structure, such as the shell of an insect, that provides protection or support for an organism.
A hard, protective outer body covering of an animal, such as an insect, crustacean, or mollusk. The exoskeletons of insects and crustaceans are largely made of chitin. Compare endoskeleton.