- a port in northwestern Turkey, on both sides of the Bosporus: built by Constantine I on the site of ancient Byzantium; capital of the Eastern Roman Empire and of the Ottoman Empire; capital removed to Ankara 1923.
- a port in NW Turkey, on the western (European) shore of the Bosporus: the largest city in Turkey; founded in about 660 bc by Greeks; refounded by Constantine the Great in 330 ad as the capital of the Eastern Roman Empire; taken by the Turks in 1453 and remained capital of the Ottoman Empire until 1922; industrial centre for shipbuilding, textiles, etc. Pop: 9 760 000 (2005 est))
