shell

The usually hard outer covering that encases certain organisms, such as insects, turtles, and most mollusks.

A similar outer covering on a nut or seed.

A similar outer covering on certain eggs, such as those of birds and reptiles; an eggshell.

The material that constitutes such a covering.

Something resembling or having the form of a shell, especially.

An external, usually hard, protective or enclosing case or cover.

A framework or exterior, as of a building.

A thin layer of pastry.

The external part of the ear.