American elder vs black elderberry

American elder and black elderberry both are nouns.

Word	Noun	Adjective	Verb	Adverb
American elder	Yes	No	No	No
black elderberry	Yes	No	No	No

As nouns, American elder and black elderberry are synonyms defined as:

American elder and black elderberry: common elder of central and eastern North America bearing purple-black berries; fruit used in wines and jellies

Other synonyms of American elder include Sambucus canadensis, sweet elder.

American elder (noun)	black elderberry (noun)
common elder of central and eastern North America bearing purple-black berries; fruit used in wines and jellies	common elder of central and eastern North America bearing purple-black berries; fruit used in wines and jellies