In the Twilight series, a singer (Italian: un(a) cantante) is a person whose blood is unusually appealing to a particular vampire; so Bella is Edward's cantante. Aro uses the term in New Moon; and Edward explains it to Alice and Bella. The term refers to the fact that the person's blood "sings" to the vampire. Note that cantante is NOT Latin (the Latin nominative singular would be cantans); moreover the words used by Aro la tua cantante mean, literally, "your singer." The words la tua are not part of the translation of the word "singer."