Lewis & Short

Plătaeae, ārum, f., = Πλαταῖαι, Platœa, a city in Bœotia, celebrated for a victory of the Greeks over the Persians, now Kokla, Cic. Off. 1, 18, 61; Nep. Arist. 2, 1; id. Paus. 1, 2; Just. 2, 12, 11 al.
Hence,

  1. A. Plătaeenses, ĭum, m., the inhabitants of Platœa, the Platœans, Nep. Milt. 5, 1; Just. 2, 9, 9.
  2. B. Plătaeēus, a, um, adj., of or belonging to Platœa, Platœan: proelium, Vitr. 1, 1.