Amongst other things, a shell is:
- An animal shell, the hard, rigid outer covering of an animal such as a mollusk or gastropod. See also: shell (material).
- The operating system shell, the command line interpreter in the Unix operating system.
- An electron shell (energy level), consisting of a number of electrons in an orbital around an atomic nucleus
- The shorthand name for Shell Oil's line of convenience stores.
- A projectile with explosive charge, shot from a gun; typically shells are larger than bullets and shot from larger guns. See shell (weapon).
- In physics, see On shell and Off shell
- shell (fruit)
- turtle shell