shadbush vs shrub

shadbush and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
shadbush	Yes	No	No	No
shrub	Yes	No	No	No

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

shadbush: any of various North American trees or shrubs having showy white flowers and edible blue-black or purplish fruit
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of shadbush include bush.

shadbush (noun)	shrub (noun)
any of various North American trees or shrubs having showy white flowers and edible blue-black or purplish fruit	a low woody perennial plant usually having several major stems