piece of land vs piece of ground

piece of land and piece of ground both are nouns.

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

As nouns, piece of land and piece of ground are synonyms defined as:

Other synonyms of piece of land include parcel, parcel of land, tract.

piece of land (noun)	piece of ground (noun)
an extended area of land	an extended area of land