operatic star vs singer

operatic star and singer both are nouns.

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

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

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

operatic star (noun)	singer (noun)
singer of lead role in an opera	a person who sings