butter vs lemon butter

butter and lemon butter both are nouns.

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

As nouns, lemon butter is a hyponym of butter; that is, lemon butter is a word with a more specific, narrower meaning than butter:

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

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

butter (verb)	lemon butter (verb)
spread butter on