shell

Webster's Dictionary (1913)

Origin: OE. shelle, schelle, AS. scell, scyll; akin to D. shel, Icel. skel, Goth. skalja a tile, and E. skill. Cf. Scale of fishes, Shale, Skill.

1. A hard outside covering, as of a fruit or an animal. Specifically: (a) The covering, or outside part, of a nut; as, a hazelnut shell. (b) A pod. (c) The hard covering of an egg.

Think him as a serpent's egg,... And kill him in the shell.— William Shakespeare

(d) Zoology The hard calcareous or chitinous external covering of mollusks, crustaceans, and some other invertebrates. In some mollusks, as the cuttlefishes, it is internal, or concealed by the mantle. Also, the hard covering of some vertebrates, as the armadillo, the tortoise, and the like. (e) Zoology Hence, by extension, any mollusks having such a covering.

2. Military A hollow projectile, of various shapes, adapted for a mortar or a cannon, and containing an explosive substance, ignited with a fuse or by percussion, by means of which the projectile is burst and its fragments scattered. See Bomb.

3. The case which holds the powder, or charge of powder and shot, used with breechloading small arms.

4. Any slight hollow structure; a framework, or exterior structure, regarded as not complete or filled in; as, the shell of a house.

5. A coarse kind of coffin; also, a thin interior coffin inclosed in a more substantial one. Knight, Edward Henry

6. An instrument of music, as a lyre, — the first lyre having been made, it is said, by drawing strings over a tortoise shell.

When Jubal struck the chorded shell.— John Dryden

7. An engraved copper roller used in print works.

8. pl. The husks of cacao seeds, a decoction of which is often used as a substitute for chocolate, cocoa, etc.

9. Nautical The outer frame or case of a block within which the sheaves revolve.

10. A light boat the frame of which is covered with thin wood or with paper; as, a racing shell.

11. Something similar in form or action to an ordnance shell; specif.: (a) Fireworks A case or cartridge containing a charge of explosive material, which bursts after having been thrown high into the air. It is often elevated through the agency of a larger firework in which it is contained. (b) Oil Wells A torpedo.

12. A concave rough cast-iron tool in which a convex lens is ground to shape.

13. A gouge bit or shell bit.

Message shell, a bombshell inside of which papers may be put, in order to convey messages. — Shell bit, a tool shaped like a gouge, used with a brace in boring wood. See Bit, noun, 3. — Shell button. (a) A button made of shell. (b) A hollow button made of two pieces, as of metal, one for the front and the other for the back, — often covered with cloth, silk, etc. — Shell cameo, a cameo cut in shell instead of stone. — Shell flower. Botany Same as Turtlehead. — Shell gland. Zoology (a) A glandular organ in which the rudimentary shell is formed in embryonic mollusks. (b) A glandular organ which secretes the eggshells of various worms, crustacea, mollusks, etc. — Shell gun, a cannon suitable for throwing shells. — Shell ibis Zoology, the openbill of India. — Shell jacket, an undress military jacket. — Shell lime, lime made by burning the shells of shellfish. — Shell marl Mineralogy, a kind of marl characterized by an abundance of shells, or fragments of shells. — Shell meat, food consisting of shellfish, or testaceous mollusks. Thomas Fuller — Shell mound. See under Mound. — Shell of a boiler, the exterior of a steam boiler, forming a case to contain the water and steam, often inclosing also flues and the furnace; the barrel of a cylindrical, or locomotive, boiler. — Shell road, a road of which the surface or bed is made of shells, as oyster shells. — Shell sand, minute fragments of shells constituting a considerable part of the seabeach in some places.

1. To strip or break off the shell of; to take out of the shell, pod, etc.; as, to shell nuts or pease; to shell oysters.

2. To separate the kernels of (an ear of Indian corn, wheat, oats, etc.) from the cob, ear, or husk.

3. To throw shells or bombs upon or into; to bombard; as, to shell a town.

To shell out, to distribute freely; to bring out or pay, as money. colloquial

1. To fall off, as a shell, crust, etc.

2. To cast the shell, or exterior covering; to fall out of the pod or husk; as, nuts shell in falling.

3. To be disengaged from the ear or husk; as, wheat or rye shells in reaping.

Webster’s Revised Unabridged Dictionary (1913), from GCIDE 0.54 · with additions: 1913 supplement

Free On-line Dictionary of Computing

<language> An early system on the Datatron 200 series.

[Listed in CACM 2(5):16 (May 1959)]. [Jargon File]

(1995-05-11)

1.<operating system> (Originally from Multics, widely propagated via Unix) The command interpreter used to pass commands to an operating system; so called because it is the part of the operating system that interfaces with the outside world.

The commonest Unix shells are the c shell (csh) and the Bourne shell (sh).

2.(Or "wrapper") Any interface program that mediates access to a special resource or server for convenience, efficiency, or security reasons; for this meaning, the usage is usually "a shell around" whatever. [Jargon File]

(1995-05-11)

The Jargon File

[orig. Multics techspeak, widely propagated via Unix]

1.[techspeak] The command interpreter used to pass commands to an operating system; so called because it is the part of the operating system that interfaces with the outside world.

2.More generally, any interface program that mediates access to a special resource or server for convenience, efficiency, or security reasons; for this meaning, the usage is usually a shell around whatever. This sort of program is also called a wrapper.

3.A skeleton program, created by hand or by another program (like, say, a parser generator), which provides the necessary incantations to set up some task and the control flow to drive it (the term driver is sometimes used synonymously). The user is meant to fill in whatever code is needed to get real work done. This usage is common in the AI and Microsoft Windows worlds, and confuses Unix hackers.

Historical note: Apparently, the original Multics shell (sense 1) was so called because it was a shell (sense 3); it ran user programs not by starting up separate processes, but by dynamically linking the programs into its own code, calling them as subroutines, and then dynamically de-linking them on return. The VMS command interpreter still does something very like this.