goat grass vs genus Aegilops

goat grass and genus Aegilops both are nouns.

Word	Noun	Adjective	Verb	Adverb
goat grass	Yes	No	No	No
genus Aegilops	Yes	No	No	No

goat grass (noun)	genus Aegilops (noun)
European grass naturalized as a weed in North America; sharp-pointed seeds cause injury when eaten by livestock	goat grass