cuticular

noun

1. the outer layer of the skin; epidermis
2. hardened skin, such as accumulates at the base and sides of a fingernail
3. Bot. a delicate, waxy layer over the outer surface of the epidermis of plants: it contains cutin and protects against water loss and parasitic infections
4. Zool. the nonliving, thick or thin, tough outer structure secreted by the epidermis in many invertebrate organisms, as insects, crustaceans, earthworms, etc.