greengrocery vs grocery store

greengrocery and grocery store both are nouns.

Word	Noun	Adjective	Verb	Adverb
greengrocery	Yes	No	No	No
grocery store	Yes	No	No	No

As nouns, grocery store is a hypernym of greengrocery; that is, grocery store is a word with a broader meaning than greengrocery:

Other hypernyms of greengrocery include food market, grocery, market.

greengrocery (noun)	grocery store (noun)
a greengrocer's grocery store	a marketplace where groceries are sold
groceries sold by a greengrocer