grace period vs time period

grace period and time period both are nouns.

Word	Noun	Adjective	Verb	Adverb
grace period	Yes	No	No	No
time period	Yes	No	No	No

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

grace period: a period of time past the deadline for fulfilling an obligation during which a penalty that would be imposed for being late is waived, especially an extended period granted as a special favor
time period: an amount of time

Other hypernyms of grace period include period, period of time.

grace period (noun)	time period (noun)
a period of time past the deadline for fulfilling an obligation during which a penalty that would be imposed for being late is waived, especially an extended period granted as a special favor	an amount of time