Choir (from Old French cuer, ‘choir [of a church]’, ‘chorus of singers’ and ultimately the Greek chorós and Latin chorus) today means a “group of singers”, in which the participants are at once interpreters and receivers of choral music performed a cappella or with instrumental accompaniment [7]. Where the group of singers performs in a dramatic setting (e.g. in opera), the choir is called a chorus. Choral singing reconciles v…