class Hexapoda vs order Mecoptera

class Hexapoda and order Mecoptera both are nouns.

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

class Hexapoda (noun)	order Mecoptera (noun)
insects; about five-sixths of all known animal species	an order of carnivorous insects usually having long membranous wings and long beaklike heads with chewing mouths at the tip