bourtree vs elderberry bush

bourtree and elderberry bush both are nouns.

Word	Noun	Adjective	Verb	Adverb
bourtree	Yes	No	No	No
elderberry bush	Yes	No	No	No

As nouns, elderberry bush is a hypernym of bourtree; that is, elderberry bush is a word with a broader meaning than bourtree:

bourtree: a common shrub with black fruit or a small tree of Europe and Asia; fruit used for wines and jellies
elderberry bush: any of numerous shrubs or small trees of temperate and subtropical Northern Hemisphere having white flowers and berrylike fruit

Other hypernyms of bourtree include elder.

bourtree (noun)	elderberry bush (noun)
a common shrub with black fruit or a small tree of Europe and Asia; fruit used for wines and jellies	any of numerous shrubs or small trees of temperate and subtropical Northern Hemisphere having white flowers and berrylike fruit