order Diptera vs class Insecta

order Diptera and class Insecta both are nouns.

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

order Diptera (noun)	class Insecta (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