Smith’s Bible Dictionary
“Ellasar” means oak
Ellasar: the city of Arioch, (Genesis 14:1) seems to be the Hebrew representative of the old Chaldean town called in the native dialect Larsa or Larancha . Larsa was a town of lower Babylonia or Chaldea, situated nearly halfway between Ur (Mugheir) and Erech (Warka), on the left bank of the Euphrates. It is now Senkereh.