epos vs rhapsody

epos and rhapsody both are nouns.

Word	Noun	Adjective	Verb	Adverb
epos	Yes	No	No	No
rhapsody	Yes	No	No	No

As nouns, rhapsody is a hyponym of epos; that is, rhapsody is a word with a more specific, narrower meaning than epos:

Other hyponyms of epos include chanson de geste, heroic, heroic meter, heroic verse.

epos (noun)	rhapsody (noun)
a long narrative poem telling of a hero's deeds	(in ancient Greece) an epic poem adapted for recitation
a body of poetry that conveys the traditions of a society by treating some epic theme	(music) a free instrumental composition in one extended movement; typically emotional or exuberant in character
	an enthusiastic expression of emotion