Lepidoptera vs class Hexapoda

Lepidoptera and class Hexapoda both are nouns.

Word	Noun	Adjective	Verb	Adverb
Lepidoptera	Yes	No	No	No
class Hexapoda	Yes	No	No	No

Lepidoptera (noun)	class Hexapoda (noun)
moths and butterflies	insects; about five-sixths of all known animal species