HOT GATES

The pass of Thermopylae, famous for being the site of a fifth-century BCE battle where the invading Persians were crushed by a coalition of Greeks, has an etymology that's surprisingly easy to pick apart. The thermo- part meant "hot" and is the same as we see in words like thermometer and thermostat. Meanwhile, the pylae part, which should be familiar from the word pylon, is a Latin-influenced variant spelling of the plural of the noun pyle, which meant "gate", "pass", or "entrance". So, together, Thermopylae meant "hot gates". This was in reference to the hot sulfur springs in the area and its function as an entrance into the region of Thessaly. In Greek mythology, it was also believed to be the entrance to the underworld, which gives the name a double meaning.