historic period vs age

historic period and age both are nouns.

Word	Noun	Adjective	Verb	Adverb
historic period	Yes	No	No	No
age	Yes	No	Yes	No

As nouns, historic period and age are synonyms defined as:

historic period and age: an era of history having some distinctive feature

historic period (noun)	age (noun)
an era of history having some distinctive feature	how long something has existed
	a time of life (usually defined in years) at which some particular qualification or power arises
	a late time of life
	an era of history having some distinctive feature
	a prolonged period of time