vocal vs lullaby

vocal and lullaby both are nouns.

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

As nouns, lullaby is a hyponym of vocal; that is, lullaby is a word with a more specific, narrower meaning than vocal:

vocal (noun)	lullaby (noun)
music intended to be performed by one or more singers, usually with instrumental accompaniment	the act of singing a quiet song to lull a child to sleep
a short musical composition with words	a quiet song intended to lull a child to sleep

vocal (adjective)	lullaby (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