We don't have synonyms for cantoris yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are clitoris, cantor and cantors.
(n) :
(music) The lower of two choral voice parts sung when a part splits into two; traditionally sung by members of the choir on the cantoris side.
(n) :
(music) That half of the choir singing cantoris parts, collectively.
(adj) :
(church architecture) Of the side of the chancel, apse, altar or choir on which the cantor's (later precentor's) stall is placed (the left hand side to a person facing the altar);
(n) :
(music) The lower of two choral voice parts sung when a part splits into two; traditionally sung by members of the choir on the cantoris side.
(n) :
(music) That half of the choir singing cantoris parts, collectively.
(adj) :
(church architecture) Of the side of the chancel, apse, altar or choir on which the cantor's (later precentor's) stall is placed (the left hand side to a person facing the altar);