creosote bush vs shrub

creosote bush and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
creosote bush	Yes	No	No	No
shrub	Yes	No	No	No

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

creosote bush: desert shrub of southwestern United States and New Mexico having persistent resinous aromatic foliage and small yellow flowers
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of creosote bush include bush.

creosote bush (noun)	shrub (noun)
desert shrub of southwestern United States and New Mexico having persistent resinous aromatic foliage and small yellow flowers	a low woody perennial plant usually having several major stems