an ancient city in Mesopotamia, the capital of Babylonia in the 2nd millennium bc. The city (of which only ruins now remain) lay on the Euphrates and was noted by classical writers for its luxury, its fortifications, and its legendary Hanging Gardens.
Greek Babulōn (from Hebrew bāḇel), also the name of the mystical city of the Apocalypse. Compare with babel
Babylon in other Oxford dictionaries
Definition of Babylon in the US English dictionary