Thermopylae (IPA pronunciation: ) (Ancient and Katharevousa Greek , Demotic ΘεÏμοπÏλες: "hot gateway") is a location in Greece where a narrow coastal passage existed in antiquity. It derives its name from several natural hot water springs. It is primarily known for the Battle of Thermopylae in 480 BC in which an overmatched Greek force held off advancing Persians under Xerxes, and the term since has been used to reference heroic resistance against a more powerful enemyOED entry for Thermopylae..