Wikipedia
Karduniaš, also transcribed Karduniash, Karaduniyaš or Karaduniše), is a Kassite term used for the kingdom centered on Babylonia and founded by the Kassite dynasty. It is used in the 1350-1335 BC Amarna letters correspondence, and is also used frequently in Middle-Assyrian and Neo-Assyrian texts to refer to the kingdom of Babylon. The name Karaduniyaš is mainly used in the letters written between Kadashman-Enlil I, or Burna-Buriash, the Kings of Babylon, and the Pharaoh of Ancient Egypt-(called: Mizri), letters EA 1-EA 11, a subcorpus of letters, ( EA for 'el Amarna'). Much later, a version of the name was used in the Babylonian Talmud as Kardunya referring to similar locations.
There are two additional letters in the 382–letter Amarna corpus that reference Karaduniyaš. The first is a damaged, and partial letter, EA 200, (with no author), regarding " Ahlameans", (similar to the Suteans); the title is: "About Ahlameans". The second letter is complete and undamaged, a letter from one of the sons of Labaya, namely Mutbaal-(Mut-Bahli, or Mut-Ba'lu), letter EA 255.