BDB4850
מְרָתַ֫יִם used as proper name, feminine = Babylon, עֲלֵה עָלֶיהָ עַלֿ ׳ הָאָרֶץ מ Jer 50:21 perhaps = Double rebellion (dual) √ מרה q. v.; DePar 182 thinks = Babylonian Marrâtim , i.e., land by the nar Marrâtu, the bitter river (Persian Gulf) = Southern Babylonia.