Poa nemoralis vs meadowgrass

Poa nemoralis and meadowgrass both are nouns.

Word	Noun	Adjective	Verb	Adverb
Poa nemoralis	Yes	No	No	No
meadowgrass	Yes	No	No	No

As nouns, meadowgrass is a hypernym of Poa nemoralis; that is, meadowgrass is a word with a broader meaning than Poa nemoralis:

Poa nemoralis: slender European grass of shady places; grown also in northeastern America and temperate Asia
meadowgrass: any of various grasses that thrive in the presence of abundant moisture

Other hypernyms of Poa nemoralis include meadow grass.

Poa nemoralis (noun)	meadowgrass (noun)
slender European grass of shady places; grown also in northeastern America and temperate Asia	any of various grasses that thrive in the presence of abundant moisture