class Aves vs order Apodiformes

class Aves and order Apodiformes both are nouns.

Word	Noun	Adjective	Verb	Adverb
class Aves	Yes	No	No	No
order Apodiformes	Yes	No	No	No

class Aves (noun)	order Apodiformes (noun)
(ornithology) the class of birds	swifts; hummingbirds