melodic phrase vs melodic line

melodic phrase and melodic line both are nouns.

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

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

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

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

melodic phrase (noun)	melodic line (noun)
a succession of notes forming a distinctive sequence	a succession of notes forming a distinctive sequence