sing vs song

sing is not a noun while song is a noun.

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

sing (noun)	song (noun)
	the act of singing
	a short musical composition with words
	the characteristic sound produced by a bird
	a distinctive or characteristic sound
	a very small sum

sing (verb)	song (verb)
make a whining, ringing, or whistling sound
divulge confidential information or secrets
to make melodious sounds
produce tones with the voice
deliver by singing