order Dinornithiformes vs class Aves

order Dinornithiformes and class Aves both are nouns.

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

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