Context: Metonymy (/ mɪˈtɒnɪmi / mi-TON-i-mee) is a figure of speech in which a thing or concept is referred to by the name of something closely associated with that thing or concept. The words metonymy and metonym come from the Greek μετωνῠμία, metōnymía, "a change of name", from μετά, metá, "after, beyond", and-ωνυμία,-ōnymía, a suffix that names figures of speech, from ὄνῠμα, ónyma or ὄνομα, ónoma, "name".

Question: the idea that concepts are represented by a common instance of the category is called?
Steam of consciousness below:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
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To answer the question, consider the following: Metonymy (/ mɪˈtɒnɪmi / mi-TON-i-mee) is a figure of speech in which a thing or concept is referred to by the name of something closely associated with that thing or concept.
So, the answer is Metonymy.