park vs piece of ground

park and piece of ground both are nouns.

Word	Noun	Adjective	Verb	Adverb
park	Yes	No	Yes	No
piece of ground	Yes	No	No	No

As nouns, piece of ground is a hypernym of park; that is, piece of ground is a word with a broader meaning than park:

park: a large area of land preserved in its natural state as public property
piece of ground: an extended area of land

Other hypernyms of park include parcel, parcel of land, piece of land, tract.

As nouns, piece of ground is a hypernym of park; that is, piece of ground is a word with a broader meaning than park:

Other hypernyms of park include parcel, parcel of land, piece of land, tract.

park (noun)	piece of ground (noun)
a facility in which ball games are played (especially baseball games)	an extended area of land
a gear position that acts as a parking brake
a large area of land preserved in its natural state as public property
a piece of open land for recreational use in an urban area
a lot where cars are parked

park (verb)	piece of ground (verb)
place temporarily
maneuver a vehicle into a parking space