1N-COUNT (龟、蟹等的)甲壳,背甲 A carapace is the protective shell on the back of some animals such as tortoises or crabs. (龟、蟹等的)甲壳,背甲 [formal]
2N-COUNT (用以自我保护的)外壳,外衣,外表 You can refer to an attitude that someone has in order to protect themselves as their carapace . (用以自我保护的)外壳,外衣,外表 [literary]