Definition of "shell" []

• The usually hard outer covering that encases certain organisms, such as mollusks, insects, and turtles; the carapace. (noun)
• A similar outer covering on an egg, fruit, or nut. (noun)
• The material that constitutes such a covering. (noun)
• Something resembling or having the form of a shell, especially: (noun)
• An external, usually hard, protective or enclosing case or cover. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "I used to listen to the sea in that shell in the sitting-room, and I tried and tried to find a name for the sound, and all at once _song_ came into my head -- _The song of the sea in the shell_."
• "The Cambridge psychologist C. S. Myers invented the term shell shock in 1915 and it soon became popular with soldiers and civilians as an informal description of the phenomenon."
• "This produced huge numbers of soldiers unable to fight for psychological reasons—up to 40 percent of battlefield casualties by some estimates.4 But at the time, doctors thought that the concussive effects of the constant shelling somehow damaged the nervous system—hence the name shell shock."