class Filicopsida vs family Athyriaceae

class Filicopsida and family Athyriaceae both are nouns.

Word	Noun	Adjective	Verb	Adverb
class Filicopsida	Yes	No	No	No
family Athyriaceae	Yes	No	No	No

class Filicopsida (noun)	family Athyriaceae (noun)
ferns	alternative names for one of a number of families into which the family Polypodiaceae has been subdivided in some classification systems