Bosporus Syllabification: (Bos·po·rus)Pronunciation: /ˈbäsp(ə)rəs/ (also Bosphorus /ˈbäsf(ə)rəs/)Definition of Bosporus a strait that connects the Black Sea with the Sea of Marmara and separates Europe from the Anatolian peninsula of western Asia. Istanbul is located at its south end. Bosporus in other Oxford dictionaries Definition of Bosporus in the British & World English dictionary