the exterior protective or supporting structure or shell of many animals (especially invertebrates) including bony or horny parts such as nails or scales or hoofs
exoskeleton详细解释
ex.o.skel.e.ton
n.(名词) A hard outer structure, such as the shell of an insect or a crustacean, that provides protection or support for an organism. 外骨骼:为生物提供保护或支持的坚硬的外部结构,象甲壳类动物或昆虫的骨盘