Etymology

Noun

1. The calcareous or chitinous external covering of mollusks, crustaceans, and some other invertebrates.

   In some mollusks, as the cuttlefish, the shell is concealed by the animal's outer mantle and is considered internal.

   Genuine mother of pearl buttons are made from sea shells.

2. The hard calcareous covering of a bird egg.
3. The exoskeleton or wing covers of certain insects.
4. The covering, or outside part, of a nut.

   The black walnut and the hickory nut, both of the same Genus as the pecan, have much thicker and harder shells than the pecan.

5. A pod containing the seeds of certain plants, such as the legume Phaseolus vulgaris.
6. Husks of cacao seeds, a decoction of which is sometimes used as a substitute or adulterant for cocoa and its products such as chocolate.
7. The conjoined scutes that comprise the "shell" (carapace) of a tortoise or turtle.
8. The overlapping hard plates comprising the armor covering the armadillo's body.
9. The accreted mineral formed around a hollow geode.
10. The casing of a self-contained single-unit artillery projectile.
11. A hollow usually spherical or cylindrical projectile fired from a seige 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 scattered at high velocity its contents and fragments. Formerly called a bomb (q.v.).
12. The cartridge of a breechloading firearm; a load; a bullet; a round.
13. Any slight hollow structure; a framework, or exterior structure, regarded as not complete or filled in, as the shell of a house.
14. A garment, usually worn by women, such as a shirt, blouse, or top, with short sleeves or no sleeves, that often fastens in the rear.
15. A coarse or flimsy coffin; a thin interior coffin enclosed within a more substantial one.
16. A string instrument, as a lyre, whose acoustical chamber is formed like a shell.

    The first lyre may have been made by drawing strings over the underside of a tortoise shell.

17. The body of a drum; the often wooden, often cylindrical acoustic chamber, with or without rims added for tuning and for attaching the drum head.
18. An engraved copper roller used in print works.
19. The watertight outer covering of the hull of a vessel, often made with planking or metal plating.
20. The outer frame or case of a block within which the sheaves revolve.
21. A light boat the frame of which is covered with thin wood, impermeable fabric, or water-proofed paper; a racing shell or dragon boat.
22. A general-purpose environment, usually command-line-oriented, within which other commands are invoked and their interactions controlled.
23. A set of atomic orbitals that have the same principal quantum number.
24. An emaciated person.

    He's lost so much weight from illness; he's a shell of his former self.

25. A psychological barrier to social interaction.

    Even after months of therapy he's still in his shell.

Verb

1. To remove the outer covering or shell of something. See sheller.
2. To bombard, to fire projectiles at.
3. To disburse or give up money, to pay. (Often used with out).