vocal vs torch song

vocal and torch song both are nouns.

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

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

vocal (noun)	torch song (noun)
music intended to be performed by one or more singers, usually with instrumental accompaniment	a popular song concerned with disappointment in love
a short musical composition with words

vocal (adjective)	torch song (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