Nudibranchia vs animal order

Nudibranchia and animal order both are nouns.

Word	Noun	Adjective	Verb	Adverb
Nudibranchia	Yes	No	No	No
animal order	Yes	No	No	No

As nouns, animal order is a hypernym of Nudibranchia; that is, animal order is a word with a broader meaning than Nudibranchia:

Nudibranchia: comprising numerous marine gastropod mollusks lacking a shell in the adult state and usually having a body like a slug
animal order: the order of animals

Nudibranchia (noun)	animal order (noun)
comprising numerous marine gastropod mollusks lacking a shell in the adult state and usually having a body like a slug	the order of animals