Breadstuff and Sour bread

Breadstuff noun - Food made from dough of flour or meal and usually raised with yeast or baking powder and then baked.

Sour bread and breadstuff are semantically related. In some cases you can replace phrase "Sour bread" with "Breadstuff", this terms are similar.

Sour bread noun - Made with a starter of a small amount of dough in which fermentation is active.

Breadstuff and sour bread are semantically related. You can use "Breadstuff" instead a noun phrase "Sour bread".