black elder vs elderberry

black elder and elderberry both are nouns.

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

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

black elder and elderberry: 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, common elder, European elder, Sambucus nigra.

black elder (noun)	elderberry (noun)
a common shrub with black fruit or a small tree of Europe and Asia; fruit used for wines and jellies	berrylike fruit of an elder used for e.g. wines and jellies
	a common shrub with black fruit or a small tree of Europe and Asia; fruit used for wines and jellies