What does exoskeletal mean?
Exoskeletal is an adjective describing anything related to, or possessing, an exoskeleton — the rigid, supportive structure found on the outside of certain animals' bodies rather than inside them. Insects, spiders, crabs, lobsters, and other arthropods are the classic examples: their exoskeletal shells provide protection, prevent water loss, and serve as attachment points for muscles, but they cannot expand, so these animals must periodically molt and regrow a larger covering as they develop. The word appears most often in biological, zoological, and paleontological writing, and it has also found a home in discussions of robotics, materials science, and science fiction, where engineers borrow exoskeletal principles to design tough, lightweight exteriors. Its natural opposite is endoskeletal, describing creatures like humans whose skeletons are internal. Though technical in register, exoskeletal is precise and widely understood in scientific contexts.
adjectiveRelating to or having an exoskeleton: a rigid external skeleton that supports and protects the body of an organism from the outside, as in insects, crustaceans, and other arthropods.
- Relating to, consisting of, or having an external skeleton, especially in arthropods such as insects, spiders, and crustaceans.
"The crab's exoskeletal armor shields it from predators, but it must be shed and regrown as the animal grows."
"The lobster's exoskeletal shell must be molted periodically to allow for growth."
"Engineers studying exoskeletal designs in beetles have drawn inspiration for impact-resistant materials."
Every crab, beetle, and scorpion you've ever seen was wearing its bones on the outside — that's exoskeletal design at work.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of exoskeletal
Exoskeletal combines the Greek prefix exo-, meaning 'outside' or 'external', with 'skeletal', from Greek skeletos, meaning 'dried up' or 'mummified', which gave English the word 'skeleton'. The compound follows the same pattern as other scientific terms built on exo-, such as exothermic and exoplanet. The adjective arose as a derivative of the noun 'exoskeleton', a term coined in nineteenth-century zoology as biologists formalized the contrast between animals with external and internal skeletons.
Related word forms
How exoskeletal is actually used
A technical term used chiefly in biology, zoology, and paleontology; rare in everyday conversation, where speakers more often refer to an animal's 'shell' or 'exoskeleton'. It also appears occasionally in science fiction and robotics writing.
Easily confused with exoskeletal
Endoskeletal describes a skeleton inside the body (as in vertebrates), while exoskeletal describes a supportive framework on the outside of the body.
Exoskeleton is the noun naming the external structure itself, whereas exoskeletal is the adjective describing things related to or possessing such a structure.