poem vs melic verse

poem and melic verse both are nouns.

Word	Noun	Adjective	Verb	Adverb
poem	Yes	No	No	No
melic verse	Yes	No	No	No

As nouns, melic verse is a hyponym of poem; that is, melic verse is a word with a more specific, narrower meaning than poem:

poem: a composition written in metrical feet forming rhythmical lines
melic verse: verse that is intended to be sung, especially Greek lyric verse of the seventh to fifth century B.C.

poem (noun)	melic verse (noun)
a composition written in metrical feet forming rhythmical lines	verse that is intended to be sung, especially Greek lyric verse of the seventh to fifth century B.C.