tune vs melody

tune and melody both are nouns.

Word	Noun	Adjective	Verb	Adverb
tune	Yes	No	Yes	No
melody	Yes	No	No	No

As nouns, tune and melody are synonyms defined as:

Other synonyms of tune include air, line, melodic line, melodic phrase, strain.

tune (noun)	melody (noun)
the adjustment of a radio receiver or other circuit to a required frequency	the perception of pleasant arrangements of musical notes
the property of producing accurately a note of a given pitch	a succession of notes forming a distinctive sequence
a succession of notes forming a distinctive sequence

tune (verb)	melody (verb)
adjust the pitches of (musical instruments)
adjust for (better) functioning