black haw vs shrub

black haw and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
black haw	Yes	No	No	No
shrub	Yes	No	No	No

As nouns, shrub is a hypernym of black haw; that is, shrub is a word with a broader meaning than black haw:

black haw: upright deciduous shrub having frosted dark-blue fruit; east and east central North America
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of black haw include bush.

black haw (noun)	shrub (noun)
upright deciduous shrub having frosted dark-blue fruit; east and east central North America	a low woody perennial plant usually having several major stems
deciduous tree of southeastern United States and Mexico