melodic theme vs melody

melodic theme and melody both are nouns.

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

As nouns, melody is a hypernym of melodic theme; that is, melody is a word with a broader meaning than melodic theme:

Other hypernyms of melodic theme include air, line, melodic line, melodic phrase, strain, tune.

melodic theme (noun)	melody (noun)
(music) melodic subject of a musical composition	the perception of pleasant arrangements of musical notes
	a succession of notes forming a distinctive sequence