tenor vs singing voice

tenor and singing voice both are nouns.

Word	Noun	Adjective	Verb	Adverb
tenor	Yes	Yes	No	No
singing voice	Yes	No	No	No

As nouns, singing voice is a hypernym of tenor; that is, singing voice is a word with a broader meaning than tenor:

tenor (noun)	singing voice (noun)
the pitch range of the highest male voice	the musical quality of the voice while singing
the general meaning or substance of an utterance
a settled or prevailing or habitual course of a person's life
the adult male singing voice above baritone
an adult male with a tenor voice

tenor (adjective)	singing voice (adjective)
of or close in range to the highest natural adult male voice
(of a musical instrument) intermediate between alto and baritone or bass