playing area vs piece of land

playing area and piece of land both are nouns.

Word	Noun	Adjective	Verb	Adverb
playing area	Yes	No	No	No
piece of land	Yes	No	No	No

As nouns, piece of land is a hypernym of playing area; that is, piece of land is a word with a broader meaning than playing area:

Other hypernyms of playing area include parcel, parcel of land, piece of ground, tract.

playing area (noun)	piece of land (noun)
a piece of land prepared for playing a game	an extended area of land