The figure of speech you are referring to is called synecdoche.
What is Synecdoche?
Synecdoche is a literary device where a part of something is used to represent the whole, or conversely, the whole is used to represent a part.
Examples:
- Part for the whole:
- "All hands on deck" — here, "hands" (a part of the sailors) represent the sailors themselves (the whole).
- "Nice wheels!" — "wheels" represent the entire car.
- Whole for a part:
- "The world watched" — "the world" (the whole) represents a large group of people (a part).
- "America won gold" — "America" (the whole country) represents a specific team or athlete.
Synecdoche is closely related to metonymy , but while metonymy uses something associated with the subject, synecdoche specifically uses a part- whole relationship. If you'd like, I can provide more examples or explain how to use synecdoche effectively in writing!