torch singer vs vocaliser

torch singer and vocaliser both are nouns.

Word	Noun	Adjective	Verb	Adverb
torch singer	Yes	No	No	No
vocaliser	Yes	No	No	No

As nouns, vocaliser is a hypernym of torch singer; that is, vocaliser is a word with a broader meaning than torch singer:

torch singer: a singer (usually a woman) who specializes in singing torch songs
vocaliser: a person who sings

Other hypernyms of torch singer include singer, vocalist, vocalizer.

torch singer (noun)	vocaliser (noun)
a singer (usually a woman) who specializes in singing torch songs	a person who sings
	an organism that can utter vocal sounds