whole wheat bread vs brown bread

whole wheat bread and brown bread both are nouns.

Word	Noun	Adjective	Verb	Adverb
whole wheat bread	Yes	No	No	No
brown bread	Yes	No	No	No

As nouns, whole wheat bread and brown bread are synonyms defined as:

Other synonyms of whole wheat bread include dark bread, whole meal bread.

whole wheat bread (noun)	brown bread (noun)
bread made with whole wheat flour	dark steamed bread made of cornmeal wheat and flour with molasses and soda and milk or water
	bread made with whole wheat flour