playing field vs tract

playing field and tract both are nouns.

Word	Noun	Adjective	Verb	Adverb
playing field	Yes	No	No	No
tract	Yes	No	No	No

As nouns, tract is a hypernym of playing field; that is, tract is a word with a broader meaning than playing field:

Other hypernyms of playing field include parcel, parcel of land, piece of ground, piece of land.

playing field (noun)	tract (noun)
a piece of land prepared for playing a game	a bundle of myelinated nerve fibers following a path through the brain
the circumstances under which competition occurs	a system of body parts that together serve some particular purpose
	a brief treatise on a subject of interest; published in the form of a booklet
	an extended area of land