class Aves vs order Dinornithiformes

class Aves and order Dinornithiformes both are nouns.

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

class Aves (noun)	order Dinornithiformes (noun)
(ornithology) the class of birds	a ratite bird order: recently extinct flightless birds of New Zealand