epos vs epic poem

epos and epic poem both are nouns.

Word	Noun	Adjective	Verb	Adverb
epos	Yes	No	No	No
epic poem	Yes	No	No	No

As nouns, epos and epic poem are synonyms defined as:

Other synonyms of epos include epic, heroic poem.

epos (noun)	epic poem (noun)
a long narrative poem telling of a hero's deeds	a long narrative poem telling of a hero's deeds
a body of poetry that conveys the traditions of a society by treating some epic theme