Salonica, SALONIKI, a city and port of Turkey in Europe situated at the head of the Gulf of Salonica, which bounds the peninsula of Chalkis on the west. The original name, Therma, was changed to Thessalonica by Cassander (B.C. 315), the founder of its importance and commercial prosperity, which was increased by the great Roman road from Dyrrachium (Durazzo) to Byzantium, the Via Egnatia, passing through it. The city is finely situated on the western slope of a hill in a fertile region. Its chief exports are corn, cotton, tobacco, and wool.