class Gastropoda vs order Pulmonata

class Gastropoda and order Pulmonata both are nouns.

Word	Noun	Adjective	Verb	Adverb
class Gastropoda	Yes	No	No	No
order Pulmonata	Yes	No	No	No

class Gastropoda (noun)	order Pulmonata (noun)
snails and slugs and their relatives	large order of gastropods usually breathing by means of a lung-like sac comprising most land snails and slugs and many freshwater snails