blue elderberry vs blue elder

blue elderberry and blue elder both are nouns.

Word	Noun	Adjective	Verb	Adverb
blue elderberry	Yes	No	No	No
blue elder	Yes	No	No	No

As nouns, blue elderberry and blue elder are synonyms defined as:

blue elderberry and blue elder: shrub or small tree of western United States having white flowers and blue berries; fruit used in wines and jellies

Other synonyms of blue elderberry include Sambucus caerulea.

blue elderberry (noun)	blue elder (noun)
shrub or small tree of western United States having white flowers and blue berries; fruit used in wines and jellies	shrub or small tree of western United States having white flowers and blue berries; fruit used in wines and jellies