From a saint's greeting to everyday use
The word was originally used in the expression Salve Jorge, a greeting to Saint George. Over time, salve broadened beyond that devotional context into an everyday way of greeting people across Brazil.
Further
Salve is the greeting — hail, or save — and it carries into the doctrine from the Salve Rainha, the Hail Holy Queen, which is among the prayers said in the works. The prayer addresses Mary as Mother of Mercy and as the hope of the banished children of Eve, and the same word opens the vivas: Viva a Rainha da Floresta. The greeting and the prayer are the same gesture at two lengths.