muffin vs quick bread

muffin and quick bread both are nouns.

Word	Noun	Adjective	Verb	Adverb
muffin	Yes	No	No	No
quick bread	Yes	No	No	No

As nouns, quick bread is a hypernym of muffin; that is, quick bread is a word with a broader meaning than muffin:

muffin: a sweet quick bread baked in a cup-shaped pan
quick bread: breads made with a leavening agent that permits immediate baking

muffin (noun)	quick bread (noun)
a sweet quick bread baked in a cup-shaped pan	breads made with a leavening agent that permits immediate baking