grassland vs parcel of land

grassland and parcel of land both are nouns.

Word	Noun	Adjective	Verb	Adverb
grassland	Yes	No	No	No
parcel of land	Yes	No	No	No

As nouns, parcel of land is a hypernym of grassland; that is, parcel of land is a word with a broader meaning than grassland:

grassland: land where grass or grasslike vegetation grows and is the dominant form of plant life
parcel of land: an extended area of land

Other hypernyms of grassland include biome, parcel, piece of ground, piece of land, tract.

grassland (noun)	parcel of land (noun)
land where grass or grasslike vegetation grows and is the dominant form of plant life	an extended area of land