Allah is a purely Arabic term used in reference to an Arabian deity. Hastings' Encyclopedia of Religion and Ethics I:326, T & T Clark, states:

'"Allah" is a proper name, applicable only to their [Arabs'] peculiar God. '

According to the Encyclopedia of Religion:

'"Allah" is a pre-Islamic name . . . corresponding to the Babylonian Bel' (Encyclopedia of Religion, I:117 Washington DC, Corpus Pub., 1979).

For those who find it hard to believe that Allah was a pagan name for a peculiar pagan Arabian deity in pre-Islamic times, the following quotations may be helpful:

"Allah is found . . . in Arabic inscriptions prior to Islam" (Encyclopedia Britannica, I:643).

"The Arabs, before the time of Mohammed, accepted and worshipped, after a fashion, a supreme god called Allah" (Encyclopedia off Islam, I:302, Leiden: E.J. Brill, 1913, Houtsma).

"Allah was known to the pre-Islamic . . . Arabs; he was one of the Meccan deities" (Encyclopedia off Islam, I:406, ed. Gibb).

Almost all of the Muslim ceremonies are the same as what the pagan Arabs already did. The circling of the Kaaba and throwing of stones. After all, this cult was invented by one single man in a few short years.
The Cult of the Moon God