Nero's crown vs shrub

Nero's crown and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
Nero's crown	Yes	No	No	No
shrub	Yes	No	No	No

As nouns, shrub is a hypernym of Nero's crown; that is, shrub is a word with a broader meaning than Nero's crown:

Nero's crown: tropical shrub having glossy foliage and fragrant nocturnal flowers with crimped or wavy corollas; northern India to Thailand
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of Nero's crown include bush.

Nero's crown (noun)	shrub (noun)
tropical shrub having glossy foliage and fragrant nocturnal flowers with crimped or wavy corollas; northern India to Thailand	a low woody perennial plant usually having several major stems