When part of an object becomes the name for the whole [duplicate]

Is there a word to describe when a part becomes the name for the whole, particularly in a jargon sense?

For example, a door to door salesman at the end of the day might talk about how many "doors" he visited, rather than houses, or a pathology nurse might talk about "doing veins" rather seeing patients?

I read a definition along these lines years and years ago, but I've completely forgotten the word. If possible I'm trying to find this same word again.

I'd say that would be a synecdoche.

A synecdoche (/sɪˈnɛkdəkiː/, si-nek-də-kee; from Greek συνεκδοχή, synekdoche, lit. "simultaneous understanding")1 is a figure of speech in which a term for a part of something refers to the whole of something or vice versa

Reference:
https://en.wikipedia.org/wiki/Synecdoche

The more common word used is metonymy. The classic examples of that would be calling a car "wheels" or a police officer a "copper" (what their badges were made of), or military officers "brass" (their button material).

me·ton·y·my məˈtänəmē/

noun: metonymy; plural noun: metonymies

the substitution of the name of an attribute or adjunct for that of the thing meant, for example suit for business executive, or the track for horse racing.