"Allah" may have also been used in pre-Islamic times to refer to the god of the moon and travel, worshiped by nomadic Arabic tribes. This Allah was considered to be the ancestor and leader of the other gods, such as the goddesses al-Lat?, al-Uzza? and Man'at?. According to Professor Carleton S. Coon in his book Southern Arabia, "The god Il or Ilah was originally a phase of the Moon God, but early in Arabian history the name became a general term for god, and it was this name that the Hebrews used prominently in their personal names, such as Emanu-el, Israel, etc." The Hebrew form of this name, El, was used as an Old Testament synonym for Yahweh.
see: the 99 Names of God