shell

noun

• 1the hard protective outer case of a mollusk or crustacean:cowrie shells the technique of carving shell
• the thin outer covering of an animal’s egg, which is hard and fragile in that of a bird but leathery in that of a reptile.
• the outer case of a nut kernel or seed.
• the carapace of a tortoise, turtle, or terrapin.
• the wing cases of a beetle.
• the integument of an insect pupa or chrysalis.
• (one's shell) used with reference to a state of shyness or introversion:she’ll soon come out of her shell with the right encouragement

• 2something resembling or likened to a shell because of its shape or its function as an outer case:pasta shells baked pastry shells filled with cheese
• the walls of an unfinished or gutted building or other structure:the hotel was a shell, the roof having collapsed completely
• an outer form without substance:he was a shell of the man he had been previously
• a light racing boat used in the sport of crew.
• the metal framework of a vehicle body.
• an inner or roughly made coffin.
• the hand guard of a sword.
• Physics each of a set of orbitals around the nucleus of an atom, occupied or able to be occupied by electrons of similar energies.

• 3an explosive artillery projectile or bomb:the sound of the shell passing over, followed by the explosion [as modifier]:shell holes
• a hollow metal or paper case used as a container for fireworks, explosives, or cartridges.
• North American a cartridge.

• 4 Computingshort for shell program.

verb

• 1 [with object] bombard with shells:the guns started shelling their positions

• 2 [with object] remove the shell or pod from (a nut or seed):they were shelling peas (as adjective shelled)shelled Brazil nuts

• 3 [no object] gather seashells:there was nothing to do except swim or go shelling on the beaches