outfield vs piece of land

outfield and piece of land both are nouns.

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

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

outfield: the area of a baseball playing field beyond the lines connecting the bases
piece of land: an extended area of land

Other hypernyms of outfield include parcel, parcel of land, piece of ground, tract.

outfield (noun)	piece of land (noun)
the area of a baseball playing field beyond the lines connecting the bases	an extended area of land