shell

S0333300 (shĕl)n.1. a. The usually hard outer covering that encases certain organisms, such as insects, turtles, and most mollusks.b. A similar outer covering on a nut or seed.c. A similar outer covering on certain eggs, such as those of birds and reptiles; an eggshell.d. The material that constitutes such a covering.2. Something resembling or having the form of a shell, especially:a. An external, usually hard, protective or enclosing case or cover.b. A framework or exterior, as of a building.c. A thin layer of pastry.d. The external part of the ear.3. Nautical a. The hull of a ship.b. A light, long, narrow racing boat propelled by rowers.4. A small glass for beer.5. a. An artillery projectile containing an explosive charge.b. A metal or cardboard case containing the charge and primer for a piece of firearms ammunition, especially one also containing shot and fired from a shotgun.6. An attitude or a manner adopted to mask one's true feelings or to protect one from perceived or real danger: Embarrassed, she withdrew into a shell.7. Physics a. A set of electron orbitals having nearly the same energy and sharing the same first quantum number.b. Any of the stable states of other particles or collections of particles (such as the nucleons in an atomic nucleus) at a given energy or small range of energies.8. a. A usually sleeveless and collarless, typically knit blouse.b. A thin, usually waterproof or windproof outer garment for the upper body.9. Computers A program that works with the operating system as a command processor, used to enter commands and initiate their execution.10. A company or corporation created by a second company or corporation for the purposes of facilitating a particular transaction, especially one that is intended to be concealed.v. shelled, shell·ing, shells v.tr.1. a. To remove the shell of; shuck: shell oysters.b. To remove from a shell: shell peas.2. To separate the kernels of (corn) from the cob.3. To fire shells at; bombard.4. a. To defeat decisively.b. Baseball To hit the pitches of (a pitcher) hard and with regularity: shelled the pitcher for eight runs in the first inning.v.intr.1. To shed or become free of a shell.2. To look for or collect shells, as on a seashore: spent the day shelling on Cape Cod.Phrasal Verb: shell out Informal To hand over; pay: had to shell out $500 in car repairs.

[Middle English, from Old English scell; see skel- in Indo-European roots.]

shell adj.shell′er n.

shell

(ʃɛl) n1. (Zoology) the protective calcareous or membranous outer layer of an egg, esp a bird's egg2. (Zoology) the hard outer covering of many molluscs that is secreted by the mantle3. (Zoology) any other hard outer layer, such as the exoskeleton of many arthropods4. (Botany) the hard outer layer of some fruits, esp of nuts5. any hard outer case6. (Firearms, Gunnery, Ordnance & Artillery) a hollow artillery projectile filled with explosive primed to explode either during flight, on impact, or after penetration. Compare ball¹^7a7. (Firearms, Gunnery, Ordnance & Artillery) a small-arms cartridge comprising a hollow casing inside which is the primer, charge, and bullet8. (Firearms, Gunnery, Ordnance & Artillery) a pyrotechnic cartridge designed to explode in the air9. (Rowing) rowing a very light narrow racing boat10. (Building) the external structure of a building, esp one that is unfinished or one that has been gutted by fire11. (Mechanical Engineering) the basic structural case of something, such as a machine, vehicle, etc12. (Atomic Physics) physics a. a class of electron orbits in an atom in which the electrons have the same principal quantum number and orbital angular momentum quantum number and differences in their energy are small compared with differences in energy between shellsb. an analogous energy state of nucleons in certain theories (shell models) of the structure of the atomic nucleus13. (Cookery) the pastry case of a pie, flan, etc14. (Building) a thin slab of concrete or a skeletal framework made of wood or metal that forms a shell-like roof15. (Education) Brit (in some schools) a class or form16. come out of one's shell to become less shy and reserved17. bring out of one's shell to help to become less shy and reservedvb18. to divest or be divested of a shell, husk, pod, etc19. to separate or be separated from an ear, husk, cob, etc20. (Firearms, Gunnery, Ordnance & Artillery) (tr) to bombard with artillery shells[Old English sciell; related to Old Norse skel shell, Gothic skalja tile, Middle Low German schelle shell; see scale¹, shale] ˈshell-less adj ˈshelly adj

shell

(ʃɛl)

n. 1. a hard outer covering of an animal, as of a clam, snail, lobster, or turtle. 2. the material constituting any of various coverings of this kind. 3. the hard exterior of an egg. 4. the usu. hard outer covering of a seed, fruit, or the like. 5. something resembling the shell of an animal, as in shape or hollowness. 6. a hard, protecting or enclosing case or cover. 7. a reserved attitude or manner. 8. a hollow projectile, as for a cannon, filled with an explosive charge. 9. a metallic cartridge used in small arms. 10. a metal or paper cartridge for use in a shotgun. 11. a cartridgelike pyrotechnic device that explodes in the air. 12. an unfilled pastry crust, as for a pie. 13. a light, long, narrow racing boat for rowing by one or more persons. 14. the framework or external structure of a building. 15. the outer part of a finished garment that has an often detachable lining. 16. a woman's sleeveless blouse or sweater. 17. the plating or planking forming the exterior hull of a ship. 18. a computer program providing a menu-driven or graphical user interface designed to simplify use of the operating system, as in loading application programs. 19. a. any of the electron orbits in an atom having the same principal quantum number and about the same energy. b. a group of nucleons of approximately the same energy. 20. tortoiseshell (def. 1). 21. the curved solid forming a domed or arched roof. 22. the metal, pressure-resistant outer casing of a fire-tube boiler. v.t. 23. to remove the shell of. 24. to separate (corn, grain, etc.) from the ear, cob, or husk. 25. to fire shells or explosive projectiles into, upon, or among; bombard. v.i. 26. to fall or come out of the shell, husk, or pod. 27. to come away or fall off, as a shell or outer coat. 28. to gather seashells. 29. shell out, Informal. to pay (money). [before 900; (n.) Old English scell (Anglian), sciell, c. Middle Dutch schelle pod, rind, Old Norse skel seashell, Gothic skalja tile] shell′-less, adj.

she'll

(ʃil; unstressed ʃɪl) contraction of she will.

shell

(shĕl)1. a. The usually hard outer covering of certain animals, such as mollusks, insects, and turtles.b. The hard outer covering of a bird's egg.c. The hard outer covering of a seed, nut, or fruit.2. Any of the regions in which electrons are concentrated around the nucleus of an atom. Depending on the number of protons in the nucleus, atoms can have up to seven shells. Electrons in the outer shells have greater energy than those in shells closer to the nucleus. An electron in an inner shell can gain energy and move to an outer shell while, if there is space available, an electron can give off energy and drop from an outer shell to an inner shell. The energy is usually given off in the form of light. The innermost shell can hold two electrons while others can hold different amounts, with the greatest amount being 32 electrons. See more at atom. See Note at metal.

shell

Past participle: shelled
Gerund: shelling

Imperative
shell
shell

Present
I shell
you shell
he/she/it shells
we shell
you shell
they shell

Preterite
I shelled
you shelled
he/she/it shelled
we shelled
you shelled
they shelled

Present Continuous
I am shelling
you are shelling
he/she/it is shelling
we are shelling
you are shelling
they are shelling

Present Perfect
I have shelled
you have shelled
he/she/it has shelled
we have shelled
you have shelled
they have shelled

Past Continuous
I was shelling
you were shelling
he/she/it was shelling
we were shelling
you were shelling
they were shelling

Past Perfect
I had shelled
you had shelled
he/she/it had shelled
we had shelled
you had shelled
they had shelled

Future
I will shell
you will shell
he/she/it will shell
we will shell
you will shell
they will shell

Future Perfect
I will have shelled
you will have shelled
he/she/it will have shelled
we will have shelled
you will have shelled
they will have shelled

Future Continuous
I will be shelling
you will be shelling
he/she/it will be shelling
we will be shelling
you will be shelling
they will be shelling

Present Perfect Continuous
I have been shelling
you have been shelling
he/she/it has been shelling
we have been shelling
you have been shelling
they have been shelling

Future Perfect Continuous
I will have been shelling
you will have been shelling
he/she/it will have been shelling
we will have been shelling
you will have been shelling
they will have been shelling

Past Perfect Continuous
I had been shelling
you had been shelling
he/she/it had been shelling
we had been shelling
you had been shelling
they had been shelling

Conditional
I would shell
you would shell
he/she/it would shell
we would shell
you would shell
they would shell

Past Conditional
I would have shelled
you would have shelled
he/she/it would have shelled
we would have shelled
you would have shelled
they would have shelled

shell

To remove nuts from their shells, or peas from their pods.

Thesaurus

Noun	1.	shell - ammunition consisting of a cylindrical metal casing containing an explosive charge and a projectile; fired from a large gunammo, ammunition - projectiles to be fired from a gunartillery shell - a shell fired by artilleryshotgun shell - a shell containing lead shot; used in shotgunsshrapnel - shell containing lead pellets that explodes in flighttank shell - a shell fired by the cannon on a tankwhizbang, whizbang shell, whizzbang - a small high-velocity shell; it makes a whizzing sound followed by a bang when it hits
	2.	shell - the material that forms the hard outer covering of many animalscarapace, cuticle, shell, shield - hard outer covering or case of certain organisms such as arthropods and turtlesanimal material - material derived from animalsmother-of-pearl, nacre - the iridescent internal layer of a mollusk shell
	3.	shell - hard outer covering or case of certain organisms such as arthropods and turtlescarapace, cuticle, shieldturtle - any of various aquatic and land reptiles having a bony shell and flipper-like limbs for swimmingarthropod - invertebrate having jointed limbs and a segmented body with an exoskeleton made of chitincuticula - the outer body wall of an insectscute - large bony or horny plate as on an armadillo or turtle or the underside of a snakemollusc, mollusk, shellfish - invertebrate having a soft unsegmented body usually enclosed in a shellshell - the material that forms the hard outer covering of many animals
	4.	shell - the hard usually fibrous outer layer of some fruits especially nutsnutshell - the shell around the kernel of a nuthull - dry outer covering of a fruit or seed or nut
	5.	shell - the exterior covering of a bird's eggeggshelleggs, egg - oval reproductive body of a fowl (especially a hen) used as foodcovering, natural covering, cover - a natural object that covers or envelops; "under a covering of dust"; "the fox was flushed from its cover"
	6.	shell - a rigid covering that envelops an object; "the satellite is covered with a smooth shell of ice"covering, natural covering, cover - a natural object that covers or envelops; "under a covering of dust"; "the fox was flushed from its cover"
	7.	shell - a very light narrow racing boat racing shellracing boat - a boat propelled by oarsmen and designed for racingracing skiff, single shell - a shell for a single oarsmanscull - a racing shell that is propelled by scullssliding seat - rower's seat that slides fore and aft
	8.	shell - the housing or outer covering of something; "the clock has a walnut case"casing, caseboot - protective casing for something that resembles a leggear box, gear case, gearbox - the shell (metal casing) in which a train of gears is sealedgrandfather clock, longcase clock - a pendulum clock enclosed in a tall narrow casehousing - a protective cover designed to contain or support a mechanical componentjacket - the tough metal shell casing for certain kinds of ammunition
	9.	shell - a metal sheathing of uniform thickness (such as the shield attached to an artillery piece to protect the gunners)scale, platearmor plate, armor plating, armour plate, plate armor, plate armour - specially hardened steel plate used to protect fortifications or vehicles from enemy firehorseshoe, shoe - U-shaped plate nailed to underside of horse's hoofshell plating - the plates covering the frame of a steel ship and corresponding to the planking of a wooden shipshield - a protective covering or structure
	10.	shell - the hard largely calcareous covering of a mollusc or a brachiopodvalve - one of the paired hinged shells of certain molluscs and of brachiopodsvalve - the entire one-piece shell of a snail and certain other molluscsscallop shell - a shell of a scallopoyster shell - a shell of an oysterphragmacone, phragmocone - the thin conical chambered internal shell (either straight or curved) of a belemniteseashell - the shell of a marine organismclamshell - the shell of a clamcovering, natural covering, cover - a natural object that covers or envelops; "under a covering of dust"; "the fox was flushed from its cover"
Verb	1.	shell - use explosives on; "The enemy has been shelling us all day"blastbomb, bombard - throw bombs at or attack with bombs; "The Americans bombed Dresden"crump - bombard with heavy shells
	2.	shell - create by using explosives; "blast a passage through the mountain"blastcreate, make - make or cause to be or to become; "make a mess in one's office"; "create a furor"
	3.	shell - fall out of the pod or husk; "The corn shelled"emerge - come out into view, as from concealment; "Suddenly, the proprietor emerged from his office"
	4.	shell - hit the pitches of hard and regularly; "He shelled the pitcher for eight runs in the first inning"hit - cause to move by striking; "hit a ball"
	5.	shell - look for and collect shells by the seashoregather - look for (food) in nature; "Our ancestors gathered nuts in the Fall"
	6.	shell - come out better in a competition, race, or conflict; "Agassi beat Becker in the tennis championship"; "We beat the competition"; "Harvard defeated Yale in the last football game"beat, beat out, vanquish, trounce, crushoutscore, outpoint - score more points than one's opponentswalk over - beat easily; "The local team walked over their old rivals for the championship"eliminate - remove from a contest or race; "The cyclist has eliminated all the competitors in the race"worst, whip, mop up, pip, rack up - defeat thoroughly; "He mopped up the floor with his opponents"whomp - beat overwhelminglyget the best, have the best, overcome - overcome, usually through no fault or weakness of the person that is overcome; "Heart disease can get the best of us"spreadeagle, rout, spread-eagle - defeat disastrouslyget the jump - be there first; "They had gotten the jump on their competitors"chicane, chouse, jockey, cheat, shaft, screw - defeat someone through trickery or deceitoutsmart, outwit, overreach, circumvent, outfox, beat - beat through cleverness and wit; "I beat the traffic"; "She outfoxed her competitors"outdo, outgo, outmatch, outperform, outstrip, surpass, exceed, surmount - be or do something to a greater degree; "her performance surpasses that of any other student I know"; "She outdoes all other athletes"; "This exceeds all my expectations"; "This car outperforms all others in its class"defeat, get the better of, overcome - win a victory over; "You must overcome all difficulties"; "defeat your enemies"; "He overcame his shyness"; "He overcame his infirmity"; "Her anger got the better of her and she blew up"surmount, master, overcome, subdue, get over - get on top of; deal with successfully; "He overcame his shyness"best, outdo, outflank, scoop, trump - get the better of; "the goal was to best the competition"outfight - to fight better than; get the better of; "the Rangers outfought the Maple Leafs"; "The French forces outfought the Germans"overmaster, overpower, overwhelm - overcome by superior forcecheckmate, mate - place an opponent's king under an attack from which it cannot escape and thus ending the game; "Kasparov checkmated his opponent after only a few moves"immobilise, immobilize - make defenselessoutplay - excel or defeat in a game; "The Knicks outplayed the Lakers"drub, lick, clobber, cream, bat, thrash - beat thoroughly and conclusively in a competition or fight; "We licked the other team on Sunday!"
	7.	shell - remove from its shell or outer covering; "shell the legumes"; "shell mussels"remove, take away, withdraw, take - remove something concrete, as by lifting, pushing, or taking off, or remove something abstract; "remove a threat"; "remove a wrapper"; "Remove the dirty dishes from the table"; "take the gun from your pocket"; "This machine withdraws heat from the environment"pod - take something out of its shell or pod; "pod peas or beans"
	8.	shell - remove the husks from; "husk corn"huskremove, take away, withdraw, take - remove something concrete, as by lifting, pushing, or taking off, or remove something abstract; "remove a threat"; "remove a wrapper"; "Remove the dirty dishes from the table"; "take the gun from your pocket"; "This machine withdraws heat from the environment"

shell

noun1. husk, case, pod, shuck They cracked the nuts and removed their shells.2. carapace, armour The baby tortoise tucked his head in his shell.3. shyness, modesty, lack of confidence, self-consciousness, nervousness, reticence, timidity, diffidence, bashfulness, timorousness, mousiness, timidness a lonely boy struggling to emerge from his shell4. frame, structure, hull, framework, skeleton, chassis The solid feel of the car's shell is impressive.5. missile, shot, bullet, slug, cartridge, pellet, projectile the whistling screech of an enemy shellverb1. remove the shells from, pod, husk, shuck (U.S.) She shelled and ate a few nuts.2. bomb, barrage, bombard, attack, strike, blitz, strafe The rebels shelled the densely-populated suburbs near the port.shell something out (with money or a specified sum of money as object) pay out, fork out (slang), expend, give, hand over, lay out (informal), disburse, ante up (informal, chiefly U.S.) You won't have to shell out a fortune for it.

Translations

壳弹壳框架炮轰甲

shell

(ʃel) noun1. the hard outer covering of a shellfish, egg, nut etc. an eggshell; A tortoise can pull its head and legs under its shell. 壳、甲 2. an outer covering or framework. After the fire, all that was left was the burned-out shell of the building. 框架，骨架 3. a metal case filled with explosives and fired from a gun etc. A shell exploded right beside him.弹壳 verb1. to remove from its shell or pod. You have to shell peas before eating them.剥去...的壳2. to fire explosive shells at. The army shelled the enemy mercilessly.炮轰ˈshellfish – plural ˈshellfish – noun any of several kinds of sea animal covered with a shell (eg oyster, crab). 甲壳类动物come out of one's shell to become more confident and less shy. 一改矜持的态度，开始与人交往 shell out to pay out (money). I had to shell out twenty dollars.支付

shell

→ 壳zhCN

Shell

shell,

in zoology, hard outer covering secreted by an animal for protection. It is also called the test, crust, or carapace. The term usually refers to the calcareous shells of the many species of mollusk but is also applied to the exoskeleton of the crab and other crustaceans, to the bony covering of the turtle, and to the hard exterior of a bird's egg. People have made use of mollusk shells since early times as receptacles for food and water, as currency (see shell moneyshell money,
medium of exchange consisting of shells, the most widely distributed type of ancient currency. Shells are particularly useful as money because they may be strung in long strips of proportionate value or they may be used to provide a single unit value in exchange.
..... Click the link for more information. ), and for ornament. The scientific study of shells is called conchology.

Bibliography

See P. A. Morris, A Field Guide to the Shells (of the Atlantic coast, 1973; the Pacific, 1974); J. M. Eisenberg, A Collector's Guide to Seashells of the World (1980); The Audubon Society Field Guide to North American Shells (1981); S. D. Romashko, The Shell Book (1984); K. R. Wye, The Simon & Schuster Pocket Guide to Shells of the World (1989); M. G. Harasewych and F. Moretzsohn, The Book of Shells (2010).

Shell

The basic structure and enclosure of a building, exclusive of any interior finishes and mechanical, plumbing, and electrical systems; often describes a deteriorated structure that has lost much of its original fabric.

Shell

a cylindrical or conical drum with open ends that is fabricated for the manufacture of steam boilers, tanks, reservoirs, and similar items made from sheet metal. Shells are obtained by rolling (for sheet thicknesses up to 40 mm) and by bending and rolling (for greater thicknesses). The joint of the shell and the bottom is closed for welding or riveting by means of shrink rings or jigs.

Shell

in engineering and elasticity theory, a solid bounded by two curvilinear surfaces the distance between which is small in comparison with the other two dimensions. The surface that bisects the shell thickness is called the middle surface. Depending on the shape of the middle surface, distinctions are made between various types of shells, such as conical or toroidal shells and cylindrical shells with circular, elliptical, or other cross sections. Shells are also classified according to the total, or Gaussian, curvature of the surface. Thus spherical, ellipsoidal, and certain other shells have positive curvature; cylindrical and conical shells have zero curvature; and hyperbolic paraboloids have negative curvature. Shells may be of constant or variable thickness. They are subdivided into single-layer, double-layer, and multilayer types. Depending on the material from which they are constructed, shells may be isotropic or anisotropic. Shells are made of reinforced concrete, steel, wood, light alloys, plastics, and other building materials.

The action of external loads on shells induces internal forces that are uniformly distributed over the thickness of the shell and are called membrane stresses, or stresses in the middle surface. External loads also induce flexural forces that form transverse forces, bending moments, and torsional moments in cross sections of the shell. Because of the presence of membrane forces, shells combine considerable rigidity and strength with comparatively low weight, differing from plates in this regard. If bending stresses can be ignored in design, the shell is said to be a zero-torque shell. The presence of torsional stresses is characteristic of regions of a shell that border on the edges; this tendency is known as the edge effect.

If the stresses are within the limits of proportionality for the shell material, the methods used to design the shell are based on functions provided by the theory of elasticity. According to the Kirchhoff-Love hypothesis, which is used most often for thin shells, any straight fiber normal to the middle surface prior to deformation remains straight and normal to the surface after deformation, and the length of the fiber remains unchanged. Moreover, it is assumed that normal stresses in a direction perpendicular to the middle surface are negligibly small in comparison with the primary stresses.

Under these conditions, the general three-dimensional problem of the theory of elasticity becomes a two-dimensional problem. This problem is solved basically by integration of a system of higher-order partial differential equations under boundary conditions determined by the character of the contact between the shell and other parts of the structure. Stresses, deformations, and displacements of various points on the shell in relation to a given load must be determined in the static design of shells for strength and rigidity. In calculations of strength, deflections of the shell along the normal to the middle surface generally may be assumed to be small in comparison with the thickness of the shell. Given this assumption, the relations between these deflections, or displacements, and deformations are linear. Hence, with regard to the theory of elasticity, the main differential equations will be linear also.

Shells must often be reinforced with ribs, mainly to ensure stability. Examples include airplane fuselages and wings and some types of thin-walled coverings.

Stability is an important consideration in shell design. A peculiarity of thin-walled shells is that the loss of stability upon a denting impact is expressed as an abrupt transition from one stable state of equilibrium to another. The critical loads that effect this transition depend on such factors as initial imperfections in the shape of the shell and initial stresses. In the case of a jolting impact, the deflections turn out to be commensurate with shell thickness; analysis of shell behavior must in this case be based on nonlinear equations.

Periodic vibrations and transient processes associated with sudden or shock loads are considered under the heading of shell dynamics. When a stream of liquid or gas flows around a shell, an unstable self-oscillating condition may occur. (The determination of this condition is the object of hydroelasticity or aero-elasticity theory.) The study of nonlinear vibrations of shells is a branch of the theory of vibrations with important applications. When considering dynamic processes of shells, relationships based on the Kirchhoff-Love hypothesis do not always turn out to be applicable; in such cases, more complex differential equations are employed.

Shell construction is widely used for building-enclosures, aircraft, ships, all-metal railroad cars, television towers, and machine parts.

REFERENCES

Ambartsumian, S. A. Teoriia anizotropnykh obolochek. Moscow, 1961.
Bolotin, V. V. Dinamicheskaia ustoichivost’ uprugikh sistem. Moscow, 1956.
Vlasov, V. Z. Obshchaia teoriia obolochek i ee primeneniia v tekhnike. Moscow-Leningrad, 1949.
Vol’mir, A. S. Gibkie plastinki i obolochki. Moscow, 1956.
Vol’mir, A. S. Nelineinaia dinamika plastinok i obolochek. Moscow, 1972.
Gol’denveizer, A. L. Teoriia uprugikh tonkikh obolochek. Moscow, 1953.
Lur’e, A. I. Statika tonkostennykh uprugikh obolochek. Moscow-Leningrad, 1947.
Mushtari, Kh. M., and K. Z. Galimov. Nelineinaia teoriia uprugikh obolochek. Kazan’, 1957.
Novozhilov, V. V. Teoriia tonkikh obolochek. Leningrad, 1951.
Chernykh, K. F. Lineinaia teoriia obolochek, parts 1–2. Leningrad, 1962–1964.

A. S. VOL’MIR

Shell

a hard protective formation that completely or partially covers the bodies of certain animals. In invertebrates, the shell originates from a thickened chitinous covering or from calcareous plates.

A chitinous shell is characteristic of certain insects (for example, Coleoptera) and lower crustaceans (for example, Notos-traca). In higher crustaceans, such as crabs, the chitinous shell is impregnated with limestone salts, which give it great toughness. Echinoderms have a shell of calcareous plates; in sea urchins the plates of the shell are closely joined. Among vertebrates, representatives of all classes—except birds—have shells. The bony shell of fossil Agnatha was especially well developed. Among extant fishes, an armor of rhomboid ganoid scales covers the bodies of the Lepidosteiformes (Holostei) and the Polypterus. An armor of bony plates protects the Loricariidae, the Ostraciontoidei, the great pipefish, and seahorses.

Among amphibians, a ventral shell was developed only in fossil Stegocephalus. Representatives of a number of extinct reptile groups had bony armor. Turtles have well-developed shells consisting of two concresced bony plates—a dorsal and a ventral —covered on the outside with horny scales. The shells of crocodiles, which are made of large bony plates covered on the outside with horny plates, are also well developed. Among mammals, the shell of the extinct glyptodonts consisted of a bony dorsal plate. A shell is characteristic of armadillos and African pangolins. In the former, it consists of separate movable and articulated bony plates, and in the latter of large, horny scales placed one on top of the other.

Shell

an external protective skeletal formation that covers the body of many invertebrates. The shell usually is loosely attached to the body and has an opening through which the animal can partially protrude to the outside. It consists of organic matter, often with an admixture of calcium carbonate, encrusted sand grains, diatomaceous carapaces, and sponge needles.

Shells characterize a number of protozoans, most mollusks, and some arthropods and brachiopods. The shells of Thecamoebina consist of a chitinous or gelatinous substance and are often attached by grains of sand and other particles previously swallowed by the animal. In most testaceous flagellates, the shell is formed from several cellulosic plates. Foraminiferan shells are most often impregnated with calcium carbonate and sometimes are encrusted with sand grains; they are rarely formed totally from organic matter. The shells, which are one-or multi-chambered, range in length from 50 microns to several centimeters.

In mollusks, the shell is secreted by a special skin fold—the mantle—and usually consists of three layers. The outer layer, the periostracum, contains the organic substance conchiolin. The innermost, or nacreous, layer, is made up of small prisms of arragonite, joined together by conchiolin, that are located angularly to the surface of the shell. The middle, or prismatic, layer consists of thin plates of arragonite that are also attached each to the other by conchiolin.

Mollusk shells are extremely diverse in size and shape. The shell of the marine bivalve mollusk Tridacna weighs up to 25 kg and reaches a length of 1.7 m. The shell of loricate mollusks consists of eight dorsal overlapping plates. In gastropods the shell resembles a conical tube and is usually wound in a spiral. Bivalve shells consist of two valves connected to each other on the dorsal side by an elastic cord (ligament) and a hinge (cardo). In some cephalopods the shell is spirally coiled and has many chambers (nautilus, fossil ammonites). The shell of some extant cephalopods is internal, since it lies under the skin of the back (cuttlefish and squid). In octopuses and some representatives of other classes of mollusks, the shell is reduced.

The shell of brachiopods consists of two valves—a dorsal one and a ventral one (unlike the right and left valves of mollusks). Ostracod shells have two lateral valves. The valves of cirripede crustaceans resemble truncated cones and are formed of several scales secreted by the mantle.

Cutting tools, scrapers, mattocks, fishhooks, musical instruments, and various ornaments have been crafted from shells. Shells have also been used as vessels, and in some countries they have served as coins (for example, the cowrie’s shell) and amulets. Mother-of-pearl, which is used in the manufacture of buttons, inlays, and other products, is obtained from shells.

Accumulations of shells have formed many sedimentary rocks. For example, the shells of crustaceans form fusulinid and nummulitic limestones, and mollusk shells form coquina and pteropod ooze.

A. V. IVANOV

Shell

a racing boat used in rowing competition and featuring extremely lightweight construction. The lines are rounded, with a length-to-width ratio of 25:1 to 35:1. The skin is made of polished laminated materials, such as veneers of expensive woods, plastics, and other materials. Shells are equipped with outriggers, sliding seats, and footrests.

What does it mean when you dream about a shell?

Shells may represent the womb and the desire to be once again sheltered, nourished, and protected from life’s problems.

shell

[shel] (architecture) A reinforced concrete arched or domed roof used over unpartitioned areas. (building construction) A building without internal partitions or furnishings. (computer science) A program that provides an interface between a user and the computer's operating system by reading commands and sending them to the operating system for execution. (design engineering) The case of a pulley block. A thin hollow cylinder. A hollow hemispherical structure. The outer wall of a vessel or tank. (geology) The crust of the earth. A thin hard layer of rock. (graphic arts) An engraved roller made of copper and used in calico printing. (metallurgy) The outer wall of a metal mold. The hard layer of sand and thermosetting plastic formed over a pattern and used as a mold wall in shell molding. The metal sleeve remaining when a billet is extruded with a dummy block at smaller diameter. A tubular casting used in preparing seamless drawn tubes. A pierced forging. (ordnance) A hollow metal projectile designed to be projected from a gun, containing or intended to contain a high-explosive, chemical, atomic, or other charge. A shotgun cartridge or a cartridge for artillery of small arms. (physics) A set of energy levels with approximately the same energy in an atom or nucleus. (zoology) A hard, usually calcareous, outer covering on an animal body, as of bivalves and turtles. The hard covering of an egg. Chitinous exoskeleton of certain arthropods.

shell

1. A hollow structure in the form of a thin, curved slab or plate whose thickness is small compared with its other dimensions and with its radii of curvature. 2. Any framework or exterior structure which is regarded as not completed or filled in. 3. An ornament similar in design to a seashell.

shell

1. the protective calcareous or membranous outer layer of an egg, esp a bird's egg 2. the hard outer covering of many molluscs that is secreted by the mantle 3. any other hard outer layer, such as the exoskeleton of many arthropods 4. the hard outer layer of some fruits, esp of nuts 5. Rowing a very light narrow racing boat 6. the basic structural case of something, such as a machine, vehicle, etc. 7. Physicsa. a class of electron orbits in an atom in which the electrons have the same principal quantum number and orbital angular momentum quantum number and differences in their energy are small compared with differences in energy between shells b. an analogous energy state of nucleons in certain theories (shell models) of the structure of the atomic nucleus 8. Brit (in some schools) a class or form

SHELL

(language)An early system on the Datatron 200 series.

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

shell

(operating system)(Originally from Multics, widelypropagated via Unix) The command interpreter used to passcommands to an operating system; so called because it is thepart of the operating system that interfaces with the outsideworld.

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

shell

(3)(Or "wrapper") Any interface program that mediates accessto a special resource or server for convenience, efficiency,or security reasons; for this meaning, the usage is usually "ashell around" whatever.

shell

The outer layer of an operating system, otherwise known as the user interface. The term originally referred to the software that processed the commands typed into the Unix operating system. For example, the Bourne shell was the original Unix command line processor, and C shell and Korn shell were developed later. The default command line interface in DOS was provided by the COMMAND.COM module, which, starting with Windows 95 was superseded by CMD.EXE. See command line and user interface.

Later, the term was applied to graphical user interfaces (GUIs). For example, the default shell in Windows is Explorer, which provides the Start menu, taskbar and desktop, but third-party choices are also available (see skin). DOS also had an alternative to the command line (see DOS Shell). See Explorer, PowerShell, Bourne shell, C shell and Korn shell.

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What does it mean when you dream about a shell?

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impression, eye

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Synonyms for shell

noun husk

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noun carapace

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noun shyness

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noun frame

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noun missile

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verb remove the shells from

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verb bomb

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phrase shell something out

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Synonyms for shell

noun ammunition consisting of a cylindrical metal casing containing an explosive charge and a projectile

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noun the material that forms the hard outer covering of many animals

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noun hard outer covering or case of certain organisms such as arthropods and turtles

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noun the hard usually fibrous outer layer of some fruits especially nuts

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noun the exterior covering of a bird's egg

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noun a rigid covering that envelops an object

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noun a very light narrow racing boat

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noun the housing or outer covering of something

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noun a metal sheathing of uniform thickness (such as the shield attached to an artillery piece to protect the gunners)

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noun the hard largely calcareous covering of a mollusc or a brachiopod

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verb use explosives on