1 on eggs/nuts/some animals
ADJ. broken, empty, hard, outer, protective, thick (figurative) She had built up a protective shell of indifference around herself. | egg (also eggshell) | cockle, conch, cowrie, fossil, mollusc, mussel, oyster, scallop, sea (also seashell), snail The garden was littered with empty snail shells. | coconut, walnut
VERB + SHELL have creatures that have shells | come out of, emerge from (often figurative) He's really come out of his shell since he met Marie. | go (back) into, retreat into, withdraw into The snail went back into its shell. | remove sth from Remove the mussels from their shells.
2 explosive weapon
ADJ. heavy | unexploded | anti-aircraft, artillery, cannon, howitzer, mortar
VERB + SHELL load | fire
SHELL + VERB fall, land | blow up, burst, crash, explode | hit sth, strike sth Two shells hit the roof. | blow sth apart/off, blow sb/sth up
SHELL + NOUN fire They braved heavy shell fire to rescue the wounded. | case/casing, fragments, splinter | crater, hole
3 outer walls of a building
ADJ. concrete | burnt-out, empty, hollow The fire reduced the school to a hollow shell.