Therma (Therme) was a town in ancient Mygdonia (which was later incorporated into Macedon), afterwards called Thessalonica, situated at the northeastern extremity of a great gulf of the Aegean Sea, called Thermaicus or Thermaeus sinus ("the Thermaic Gulf") in Latin, after the town. This gulf was also called Macedonicus sinus ("the Macedonian Gulf"). Its modern name is the Gulf of Salonica.