English muffin vs breadstuff

English muffin and breadstuff both are nouns.

Word	Noun	Adjective	Verb	Adverb
English muffin	Yes	No	No	No
breadstuff	Yes	No	No	No

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

English muffin: round, raised muffin cooked on a griddle; usually split and toasted before being eaten
breadstuff: food made from dough of flour or meal and usually raised with yeast or baking powder and then baked

Other hypernyms of English muffin include bread, staff of life.

English muffin (noun)	breadstuff (noun)
round, raised muffin cooked on a griddle; usually split and toasted before being eaten	food made from dough of flour or meal and usually raised with yeast or baking powder and then baked
	flour or meal or grain used in baking bread