Therma (Therme) (Θέρμα,Θέρμη ) was a Greek city founed by Eretrians or Corinthians in late 7th century BC in ancient Mygdonia (which was later incorporated into Macedon), situated at the northeastern extremity of a great gulf of the Aegean Sea, the Thermaic Gulf. Therma was later renamed Thessalonica by Cassander.