mer-a-tha'-im (merathayim "double rebellion"): A name used for Babylon in Jeremiah 50:21. According to Delitzsch it may be equivalent to the Babylonian Marratun, i.e. land by the nar Marratu, "the bitter river" (Persian Gulf) = Southern Babylonia (OHL, under the word).
Strong's HebrewH4850: Merathayim
perhaps "double rebellion," another name for Bab.