Babylonia Syllabification: (Bab·y·lo·ni·a)Pronunciation: /ˌbabəˈlōnēə/Definition of Babylonia an ancient region of Mesopotamia, formed when the kingdoms of Akkad in the north and Sumer in the south combined in the first half of the 2nd millennium bc. Babylonia in other Oxford dictionaries Definition of Babylonia in the British & World English dictionary