black elder vs common elder

black elder and common elder both are nouns.

Word	Noun	Adjective	Verb	Adverb
black elder	Yes	No	No	No
common elder	Yes	No	No	No

As nouns, black elder and common elder are synonyms defined as:

black elder and common elder: a common shrub with black fruit or a small tree of Europe and Asia; fruit used for wines and jellies

Other synonyms of black elder include bourtree, elderberry, European elder, Sambucus nigra.

black elder (noun)	common elder (noun)
a common shrub with black fruit or a small tree of Europe and Asia; fruit used for wines and jellies	a common shrub with black fruit or a small tree of Europe and Asia; fruit used for wines and jellies