Proper noun
Cisplatina
The former Cisplatina Province or Cisplatine Province (Província Cisplatina), a province on this side of the River Plate (from the Brazilian perspective); it existed in the 1820s and was a focus of the Cisplatine War but then became part of what is now Uruguay.
Cisplatina (today's sovereign state of Uruguay), in the south, was one of the last additions to the territory of Brazil under Portuguese rule. Source: Internet