grevillea vs shrub

grevillea and shrub both are nouns.

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

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

Other hypernyms of grevillea include bush.

grevillea (noun)	shrub (noun)
any shrub or tree of the genus Grevillea	a low woody perennial plant usually having several major stems