IPA: /ˈmɛtəˌnɪm/
KK: /ˈmɛtəˌnɪm/
A word that represents something closely related to it, often used in place of the thing itself.
In the phrase 'the White House announced a new policy', 'the White House' is a metonym for the U.S. government.
Metonym is formed from "meta-" (meaning change) and "onym" (from Greek "onoma", meaning name). The word refers to a figure of speech where one term is substituted for another with which it is closely associated, thus representing a change in name.
Think of 'meta-' meaning change and 'onym' meaning name — this helps you remember that a metonym is a word that represents a change in name for something closely related.