whole meal bread vs dark bread

whole meal bread and dark bread both are nouns.

Word	Noun	Adjective	Verb	Adverb
whole meal bread	Yes	No	No	No
dark bread	Yes	No	No	No

As nouns, whole meal bread and dark bread are synonyms defined as:

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

whole meal bread (noun)	dark bread (noun)
bread made with whole wheat flour	bread made with whole wheat flour