Answer:
The term "synecdoche" is a type of figure of speech. It can mean to use a word for a part as a whole, or an item as a substitute for an entire group, or to represent an object by its function. This is reflected by many idiomatic uses of words.
Examples:
The captain ordered all hands on deck. (here short for deckhands, or sailors)
Their eyes followed him wherever he went.
He lost his wheels for the weekend. (car)
The world treated him badly.
Twenty sails came into the harbor.
Give us this day our daily bread.
Few businesses refuse to accept plastic. (credit cards)
"Friends, Romans, countrymen, lend me your ears." (from Julius Caesar)