Shell may refer to:

Architecture and design

Shell (structure) A shell is a three-dimensional solid structural element whose thickness is very small compared to its other dimensions. It is characterized in structural terms by mid-plane stress which is both coplanar and normal to the surface. A shell can be ...

, a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses

Science

Biology

* Seashell, a hard outer layer of a marine animal, found on beaches * Eggshell * Nutshell *

Exoskeleton An exoskeleton () . is a skeleton that is on the exterior of an animal in the form of hardened integument, which both supports the body's shape and protects the internal organs, in contrast to an internal endoskeleton (e.g. human skeleton, that ...

, an external covering of some animals ** Mollusc shell ***

Bivalve shell A bivalve shell is the enveloping exoskeleton or mollusc shell, shell of a bivalve mollusc, composed of two hinged halves or ''valve (mollusc), valves''. The two half-shells, called the "right valve" and "left valve", are joined by a ligament and ...

***

Gastropod shell The gastropod shell is part of the body of many gastropods, including snails, a kind of mollusc. The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium ...

** Shell, of a

brachiopod Brachiopods (), phylum (biology), phylum Brachiopoda, are a phylum of animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear e ...

* Turtle shell * Armadillo shell

Physics and chemistry

* Electron shell or a principal energy level of electrons outside an atom's nucleus * Nuclear shell model, a principal energy level of nucleons within an atom's nucleus * On shell and off shell, quantum field theory concepts depending on whether classical equations of motion are obeyed

Mathematics

* Spherical shell

Organisations

* Shell plc formerly Royal Dutch Shell plc, a British multinational oil and gas company ** Shell Oil Company or Shell USA ** Shell Australia ** Shell Canada ** Shell Nigeria *

Shell corporation A shell corporation is a company or corporation with no significant assets or operations often formed to obtain financing before beginning business. Shell companies were primarily vehicles for lawfully hiding the identity of their beneficial ...

, a type of company that serves as a vehicle for business transactions

Computing

Shell (computing) An operating system shell is a computer program that provides relatively broad and direct access to the system on which it runs. The term ''shell'' refers to how it is a relatively thin Abstraction layer, layer around an operating system. A sh ...

, a type of user interface **

Command-line interface A command-line interface (CLI) is a means of interacting with software via command (computing), commands each formatted as a line of text. Command-line interfaces emerged in the mid-1960s, on computer terminals, as an interactive and more user ...

, sometimes referred to as command shell ** List of command-line interpreters, programs occasionally referred to as shells ** Web shell, interface that enables a web server to be remotely accessed *

Read–eval–print loop A read–eval–print loop (REPL), also termed an interactive toplevel or language shell, is a simple interactive computer programming environment that takes single user inputs, executes them, and returns the result to the user; a program written ...

, also known as a language shell * Shell account, a user account on a remote server * Secure Shell, cryptographic network protocol * Shellsort or Shell sort, a sorting algorithm by Donald Shell * Shell, an empty expert system

Entertainment

* ''Shell'' (2012 film), an independent drama film * ''Shell'' (2024 film), an American thriller film * Shell (theater), a curved surface for reflecting sound * The Shells, a musical group * "Shell (Of a Man)", a song by Saya Gray from ''SAYA'', 2025 * "Shells" (''Angel''), a TV episode * "The Shell" (''The Amazing World of Gumball''), a TV episode * Shell, a receptacle used in the Shell game * "Shell", a song by Arrested Development from '' Zingalamaduni''

Places

* Shell, Ecuador * Shell, Worcestershire, England * Shell, Wyoming, United States * Shell Lake (disambiguation), several places

Weaponry

Shell (projectile) A shell, in a modern military context, is a projectile whose payload contains an explosive, incendiary device, incendiary, or other chemical filling. Originally it was called a bombshell, but "shell" has come to be unambiguous in a military ...

, an explosive device fired from artillery * Shotgun shell, a type of shotgun ammunition

Persons with the surname Shell

* Art Shell (born 1946), American football player and coach * Brandon Shell (born 1992), American football player * Donald Shell (1924–2015), American computer scientist * Donnie Shell (born 1952), American football player * George Shell (disambiguation) * Karl Shell (born 1938), American economist * Rita Shell (1863–1950), British magazine editor

Other uses

Racing shell In watercraft, a racing shell (also referred to as a ''fine boat'' (UK) or simply a ''shell'') is an extremely narrow, and often comparatively long, rowing boat specifically designed for Rowing (sport), racing or exercise. It is equipped with lon ...

, a watercraft * Shell (machinery), each half of a two-piece plain bearing * Coverage shell, the number of defenders guarding the deep portion of the field in American football * Conchiglie, a type of pasta