tune vs melodic line

tune and melodic line both are nouns.

Word	Noun	Adjective	Verb	Adverb
tune	Yes	No	Yes	No
melodic line	Yes	No	No	No

As nouns, tune and melodic line are synonyms defined as:

tune and melodic line: a succession of notes forming a distinctive sequence

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

tune (noun)	melodic line (noun)
the adjustment of a radio receiver or other circuit to a required frequency	a succession of notes forming a distinctive sequence
the property of producing accurately a note of a given pitch
a succession of notes forming a distinctive sequence

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