cuticle cuticle /ˈkjuːtɪkəl/

noun

1. Hard outer covering or case of certain organisms such as arthropods and turtles  ( carapace , cuticle , shield , shell )
   hard outer covering or case of certain organisms such as arthropods and turtles
     The hermit crab sought a new shell, carefully choosing the perfect fit for its growing body.
   The hermit crab sought a new shell, carefully choosing the perfect fit for its growing body.
   
2. The outer layer of the skin covering the exterior body surface of vertebrates  ( cuticle , epidermis )
   the outer layer of the skin covering the exterior body surface of vertebrates
   
3. The dead skin at the base of a fingernail or toenail  ( cuticle )
   the dead skin at the base of a fingernail or toenail
    She pushed back her cuticles and painted her nails with bright red polish
   She pushed back her cuticles and painted her nails with bright red polish