****Allah -- which is simply the Arabic word for God, meaning the God of Abraham ****
Some Imams have tried to say this but tracing entemology of words and study of ancient Sumerian hyroglyphs pretty much disproves it. That an Arab would claim to be heir to any monotheistic religion prior to Mohammed is laughable anyway.
You are very ignorant in claiming that Arab monotheism began with Mohammed. A significant part of the Arab world was either Orthodox Christian or Monophysite Christian in Mohammed's time. Archeological digs have found Orthodox Churches on the shores of the Persian Gulf. My bishop's family came from a valley in Syria whose Arabic name means "The Valley of the Christians" because its in habitants have held out against the Jihad from the beginning. St. Ephriam the Syrian and St. John of Damascus were Arabs. The Nestorian Church (predating Mohammed by ~300 years) still exists in Iraq.
Mohammed himself consciously rejected the Gospel which many of his fellow-Arabs had embraced. He had a Christian wife, Mary, whom he abused for refusing to convert to his false doctrine (perhaps we should venerate her as a confessor). I have said it before on other threads, at its roots, Islam is antichrist in the sense the Holy Evangelist and Apostle John the Theologian used the word in his epistles.