Noun

• A hard rigid usually large covering of an animal.
• The outside part of a fruit or seed.
• Something like an external structure that resembles a shell.
• A casing without substance.
• The hard exterior of an egg.
• A hard enclosing cover.

Verb

• To take out of the shell.
• To fall out of the shell.
• To cast the external covering.
• To gather shells from a beach.