order Picariae vs class Aves

order Picariae and class Aves both are nouns.

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

order Picariae (noun)	class Aves (noun)
term used in some classifications as nearly equivalent to the order Coraciiformes	(ornithology) the class of birds