sourdough bread vs bread

sourdough bread and bread both are nouns.

Word	Noun	Adjective	Verb	Adverb
sourdough bread	Yes	No	No	No
bread	Yes	No	Yes	No

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

sourdough bread: made with a starter of a small amount of dough in which fermentation is active
bread: food made from dough of flour or meal and usually raised with yeast or baking powder and then baked

Other hypernyms of sourdough bread include breadstuff, staff of life.

sourdough bread (noun)	bread (noun)
made with a starter of a small amount of dough in which fermentation is active	food made from dough of flour or meal and usually raised with yeast or baking powder and then baked
	informal terms for money

sourdough bread (verb)	bread (verb)
	cover with bread crumbs