A synecdoche is a type of metaphor where a part represents the whole or vice versa. It can also be where a single instance is used to represent the group, a genus for a species or some other key quality of a thing to represent the thing as a whole.
Some people refer to their home as their "crib". (This is two steps away, since most older people don't sleep in a crib.)
"She has a new set of wheels." is a synecdoche, when she really has a new car, wheels are just a part of it.
"Give us this day our daily bread." -- Christian Bible, Matthew 6:11
- In this case, "bread" refers to food or sustenance.
- "All hands on deck" is a synecdoche, meaning everybody on the deck.
- See the definition of synecdoche within A Glossary of Literary Terms , copyright 1997 by Robert Harris