Emily Dickinson Lexicon

SHELL, n. [Sax. scyl, scyll, scell, a shell, and sceale, a scale; D. schil, schaal; G. schale; Dan. and Sw. skal; Fr. ecaille. The word primarily signifies that which is peeled or separated, as rind or the outer coat of plants, or their fruit; and as shells were used for dishes, the word came to signify a dish. See Scale.]

1. The hard or stony covering of certain fruits, and of certain animals; as, the shell of a nut; the shell of an oyster or lobster. The shells of animals are crustaceous or testaceous; crustaceous, as that of the lobster, and testaceous, as that of the oyster and clam.
2. The outer coat of an egg.
3. The outer part of a house unfinished. We say of a building that wants the interior timbers or finishing, that it is a mere shell.
4. An instrument of music, like testudo in Latin; the first lyre being made, it is said, by drawing strings over a tortoise-shell. – Dryden.
5. Outer or superficial part; as, the shell of religion. – Ayliffe.
6. A bomb. Fossil shells, shells dug from the earth.