order Diptera vs class Hexapoda

order Diptera and class Hexapoda both are nouns.

Word	Noun	Adjective	Verb	Adverb
order Diptera	Yes	No	No	No
class Hexapoda	Yes	No	No	No

order Diptera (noun)	class Hexapoda (noun)
a large order of insects having a single pair of wings and sucking or piercing mouths; includes true flies and mosquitoes and gnats and crane flies	insects; about five-sixths of all known animal species