playing period vs quantity

playing period and quantity both are nouns.

Word	Noun	Adjective	Verb	Adverb
playing period	Yes	No	No	No
quantity	Yes	No	No	No

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

playing period: (in games or plays or other performances) the time during which play proceeds
quantity: how much there is or how many there are of something that you can quantify

Other hypernyms of playing period include amount, measure.

playing period (noun)	quantity (noun)
(in games or plays or other performances) the time during which play proceeds	how much there is or how many there are of something that you can quantify
	an adequate or large amount
	the concept that something has a magnitude and can be represented in mathematical expressions by a constant or a variable