It means born, resident or related to La Plata. You can refer to the city of La Plata in Argentina or to the municipality of La Plata in the Department of Huila in Colombia. In Colombia to the natives of La Plata say Platenses or Platenos. Related to the Río de La Plata.
. says, argentina-provincia Buenos Aires, for children born in town of Republic: La Plata, capital of the province of Buenos Aires -