class Hexapoda vs order Hemiptera

class Hexapoda and order Hemiptera both are nouns.

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

class Hexapoda (noun)	order Hemiptera (noun)
insects; about five-sixths of all known animal species	plant bugs, bedbugs, some true bugs; also includes suborders Heteroptera (true bugs) and Homoptera (e.g., aphids, plant lice and cicadas)