bronze age vs time period

bronze age and time period both are nouns.

Word	Noun	Adjective	Verb	Adverb
bronze age	Yes	No	No	No
time period	Yes	No	No	No

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

bronze age: (classical mythology) the third age of the world, marked by war and violence
time period: an amount of time

Other hypernyms of bronze age include period, period of time.

bronze age (noun)	time period (noun)
(classical mythology) the third age of the world, marked by war and violence	an amount of time