operatic star vs vocaliser

operatic star and vocaliser both are nouns.

Word	Noun	Adjective	Verb	Adverb
operatic star	Yes	No	No	No
vocaliser	Yes	No	No	No

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

Other hypernyms of operatic star include singer, vocalist, vocalizer.

operatic star (noun)	vocaliser (noun)
singer of lead role in an opera	a person who sings
	an organism that can utter vocal sounds