alto vs vocaliser

alto and vocaliser both are nouns.

Word	Noun	Adjective	Verb	Adverb
alto	Yes	Yes	No	No
vocaliser	Yes	No	No	No

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

Other hypernyms of alto include singer, vocalist, vocalizer.

alto (noun)	vocaliser (noun)
the pitch range of the lowest female voice	a person who sings
(of a musical instrument) the second highest instrument in a family of musical instruments	an organism that can utter vocal sounds
the lowest female singing voice
the highest adult male singing voice
a singer whose voice lies in the alto clef

alto (adjective)	vocaliser (adjective)
(of a musical instrument) second highest member of a group
of or being the highest male voice; having a range above that of tenor
of or being the lowest female voice