family Poaceae vs genus Agrostis

family Poaceae and genus Agrostis both are nouns.

Word	Noun	Adjective	Verb	Adverb
family Poaceae	Yes	No	No	No
genus Agrostis	Yes	No	No	No

family Poaceae (noun)	genus Agrostis (noun)
the grasses: chiefly herbaceous but some woody plants including cereals, bamboo, reeds, sugar cane	annual or perennial grasses cosmopolitan in Northern Hemisphere: bent grass (so named from `bent' meaning an area of unfenced grassland)