glacial period vs glacial epoch

glacial period and glacial epoch both are nouns.

Word	Noun	Adjective	Verb	Adverb
glacial period	Yes	No	No	No
glacial epoch	Yes	No	No	No

As nouns, glacial period and glacial epoch are synonyms defined as:

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

Other synonyms of glacial period include ice age.

glacial period (noun)	glacial epoch (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