筒形钻

Shell \Shell\, n. [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. --Shak.
(d) (Zo["o]l.) 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) (Zo["o]l.) Hence, by extension, any mollusks having
such a covering.

2. (Mil.) 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.

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. --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. (Naut.) 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.
[Webster 1913 Suppl.]

12. A concave rough cast-iron tool in which a convex lens is
ground to shape.
[Webster 1913 Suppl.]

13. A gouge bit or shell bit.
[Webster 1913 Suppl.]

{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}, n., 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}. (Bot.) Same as {Turtlehead}.

{Shell gland}. (Zo["o]l.)
(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} (Zo["o]l.), the openbill of India.

{Shell jacket}, an undress military jacket.

{Shell lime}, lime made by burning the shells of shellfish.


{Shell marl} (Min.), a kind of marl characterized by an
abundance of shells, or fragments of shells.

{Shell meat}, food consisting of shellfish, or testaceous
mollusks. --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.