genus Zea vs grass family

genus Zea and grass family both are nouns.

Word	Noun	Adjective	Verb	Adverb
genus Zea	Yes	No	No	No
grass family	Yes	No	No	No

genus Zea (noun)	grass family (noun)
corn	the grasses: chiefly herbaceous but some woody plants including cereals, bamboo, reeds, sugar cane