reign vs time period

reign and time period both are nouns.

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

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

Other hypernyms of reign include period, period of time.

reign (noun)	time period (noun)
royal authority; the dominion of a monarch	an amount of time
the period during which a monarch is sovereign
a period during which something or somebody is dominant or powerful

reign (verb)	time period (verb)
have sovereign power
be larger in number, quantity, power, status or importance