an ancient town in W central Italy, originally at the mouth of the Tiber but now about 6 km (4 miles) inland: served as the port of ancient Rome; harbours built by Claudius and Trajan; ruins excavated since 1854
Ostia in American English
(ˈɑstiə)
ancient city in Latium, at the mouth of the Tiber, that was the port of Rome