Arthropoda vs class Insecta

Arthropoda and class Insecta both are nouns.

Word	Noun	Adjective	Verb	Adverb
Arthropoda	Yes	No	No	No
class Insecta	Yes	No	No	No

Arthropoda (noun)	class Insecta (noun)
jointed-foot invertebrates: arachnids, crustaceans, insects, millipedes, centipedes	insects; about five-sixths of all known animal species