Marattiaceae vs fern family

Marattiaceae and fern family both are nouns.

Word	Noun	Adjective	Verb	Adverb
Marattiaceae	Yes	No	No	No
fern family	Yes	No	No	No

As nouns, fern family is a hypernym of Marattiaceae; that is, fern family is a word with a broader meaning than Marattiaceae:

Marattiaceae: constituting the order Marattiales: chiefly tropical eusporangiate ferns with gigantic fronds
fern family: families of ferns and fern allies

Marattiaceae (noun)	fern family (noun)
constituting the order Marattiales: chiefly tropical eusporangiate ferns with gigantic fronds	families of ferns and fern allies