If slaughterhouses had glass walls, everyone would be vegetarian.
—Paul and Linda McCartney
synecdoche
A figure of speech in which a part is used to designate the whole or the whole is used to designate a part. For example, the phrase "all hands on deck" means "all men on deck," not just their hands. The reverse situation, in which the whole is used for a part, occurs in the sentence "The U.S. beat Russia in the final game," where the U.S. and Russia stand for "the U.S. team" and "the Russian team," respectively.