glacial epoch vs ice age

glacial epoch and ice age both are nouns.

Word	Noun	Adjective	Verb	Adverb
glacial epoch	Yes	No	No	No
ice age	Yes	No	No	No

As nouns, glacial epoch and ice age are synonyms defined as:

glacial epoch and ice age: any period of time during which glaciers covered a large part of the earth's surface

Other synonyms of glacial epoch include glacial period.

glacial epoch (noun)	ice age (noun)
any period of time during which glaciers covered a large part of the earth's surface	any period of time during which glaciers covered a large part of the earth's surface