order Psittaciformes vs class Aves

order Psittaciformes and class Aves both are nouns.

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

order Psittaciformes (noun)	class Aves (noun)
an order of birds including parrots and amazons and cockatoos and lorikeets and lories and macaws and parakeets	(ornithology) the class of birds