rye bread vs breadstuff

rye bread and breadstuff both are nouns.

Word	Noun	Adjective	Verb	Adverb
rye bread	Yes	No	No	No
breadstuff	Yes	No	No	No

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

rye bread: any of various breads made entirely or partly with rye flour
breadstuff: food made from dough of flour or meal and usually raised with yeast or baking powder and then baked

Other hypernyms of rye bread include bread, staff of life.

rye bread (noun)	breadstuff (noun)
any of various breads made entirely or partly with rye flour	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