noun
Biological term for the hard outer structure of arthropods and some other animals. Contrasts with 内骨格 (endoskeleton).
See also: 内骨格
昆虫は外骨格を持っている。
Insects have an exoskeleton.
内骨格 means 'endoskeleton', the internal skeleton of vertebrates, while 外骨格 is the external skeleton of arthropods.
Compound of 外 (outside) and 骨格 (skeleton), a straightforward calque or translation of the English 'exoskeleton'.