Definition of "shell"
shell
noun
plural shells
(weaponry) A hollow, usually spherical or cylindrical projectile fired from a siege mortar or a smoothbore cannon. It contains an explosive substance designed to be ignited by a fuse or by percussion at the target site so that it will burst and scatter at high velocity its contents and fragments. Formerly called a bomb.
(computing) An operating system software user interface, whose primary purpose is to launch other programs and control their interactions; the user's command interpreter. Shell is a way to separate the internal complexity of the implementation of the command from the user. The internals can change while the user experience/interface remains the same.
verb
third-person singular simple present shells, present participle shelling, simple past and past participle shelled