song vs vocal

song and vocal both are nouns.

Word	Noun	Adjective	Verb	Adverb
song	Yes	No	No	No
vocal	Yes	Yes	No	No

As nouns, song and vocal are synonyms defined as:

song (noun)	vocal (noun)
the act of singing	music intended to be performed by one or more singers, usually with instrumental accompaniment
a short musical composition with words	a short musical composition with words
the characteristic sound produced by a bird
a distinctive or characteristic sound
a very small sum

song (adjective)	vocal (adjective)
	having or using the power to produce speech or sound
	relating to or designed for or using the singing voice
	given to expressing yourself freely or insistently
	full of the sound of voices