brown butter vs butter

brown butter and butter both are nouns.

Word	Noun	Adjective	Verb	Adverb
brown butter	Yes	No	No	No
butter	Yes	No	Yes	No

As nouns, butter is a hypernym of brown butter; that is, butter is a word with a broader meaning than brown butter:

brown butter: clarified butter browned slowly and seasoned with vinegar or lemon juice and capers
butter: an edible emulsion of fat globules made by churning milk or cream; for cooking and table use

brown butter (noun)	butter (noun)
clarified butter browned slowly and seasoned with vinegar or lemon juice and capers	an edible emulsion of fat globules made by churning milk or cream; for cooking and table use
	a fighter who strikes the opponent with his head

brown butter (verb)	butter (verb)
	spread butter on