melodic theme vs theme

melodic theme and theme both are nouns.

Word	Noun	Adjective	Verb	Adverb
melodic theme	Yes	No	No	No
theme	Yes	No	Yes	No

As nouns, melodic theme and theme are synonyms defined as:

melodic theme and theme: (music) melodic subject of a musical composition

Other synonyms of melodic theme include idea, musical theme.

melodic theme (noun)	theme (noun)
(music) melodic subject of a musical composition	a unifying idea that is a recurrent element in literary or artistic work
	the subject matter of a conversation or discussion
	an essay (especially one written as an assignment)
	(music) melodic subject of a musical composition
	(linguistics) the form of a word after all affixes are removed

melodic theme (verb)	theme (verb)
	provide with a particular theme or motive