meadow grass vs family Poaceae

meadow grass and family Poaceae both are nouns.

Word	Noun	Adjective	Verb	Adverb
meadow grass	Yes	No	No	No
family Poaceae	Yes	No	No	No

meadow grass (noun)	family Poaceae (noun)
any of various grasses that thrive in the presence of abundant moisture	the grasses: chiefly herbaceous but some woody plants including cereals, bamboo, reeds, sugar cane