Metonymy is the use of a linked term to stand in for an object or concept. You'll find examples of metonymy used frequently in both literature and everyday

the substitution of the name of an attribute or adjunct for that of the thing meant,

for example suit for business executive, or the turf for horse racing.

What is a metonymy example?

For example, take the phrase “the pen is mightier than the sword,” which contains two examples of metonymy. “Pen” and “sword” are everyday words, but when substituted for “written words” and “military force,” their meaning become much more symbolic.

:

a figure of speech consisting of the use of the name of one thing for that of another of which it is an attribute or with which it is associated (such as "crown" in "lands belonging to the crown")

https://www.merriam-webster.com/words-at-play/synecdoche-metonymy-usage-differences

'Synecdoche' a figure of speech in which a part is made to represent the whole or vice versa, as in England lost by six wickets (meaning ‘ the English cricket team’).

is when the word for a part of something is used to refer to the whole thing, or less commonly, the word for a whole is used to refer to a part. 'Metonymy' is when a word associated with something is used to refer to the thing itself.

The terms metonymy and synecdoche refer to two similar figures of speech often used as literary devices. (They're easy to confuse, so feel free to read this as many times as you need.)

What to Know

Synecdoche refers to a figure of speech in which the word for a part of something is used to refer to the thing itself (as hired hand for “worker”), or less commonly, the word for a thing itself is used to refer to part of that thing (as when society denotes "high society"). In metonymy, a word that is associated with something is used to refer to that thing (as when crown is used to mean "king" or "queen").

Examples of Different Forms of Synecdoche

• The phrase "hired hands" can be used to refer to workers.

• The word "head" can refer to counting cattle or people.

• The word "bread" can be used to represent food.

• The word "wheels" refers to a vehicle.

• The word "boots" refers to soldiers.