It should not come as a surprise that the word "Allah" was not something invented by Muhammad or revealed for the first time in the Quran.
There is no reason, therefore, to accept the idea that Allah passed to the Muslims from the Christians and Jews" (Islam: Beliefs and Observations, New York, Barrons, 1987, p. 28).
According to Middle East scholar E.M. Wherry, whose translation of the Quran is still used today, in pre-Islamic times Allah-worship, as well as the worship of Ba-al, were both astral religions in that they involved the worship of the sun, the moon, and the stars (A Comprehensive Commentary on the Quran, Osnabruck: Otto Zeller Verlag, 1973, p. 36).
The well-known Middle East scholar H.A.R. Gibb has pointed out that the reason that Muhammad never had to explain who Allah was in the Quran is that his listeners had already heard about Allah long before Muhammad was ever born (Mohammedanism: An Historical Survey, New York: Mentor Books, 1955, p.38).
Dr. Arthur Jeffery, one of the foremost Western Islamic scholars in modern times and professor of Islamic and Middle East Studies at Columbia University, notes:
"The name Allah, as the Quran itself is witness, was well known in pre-Islamic Arabia. Indeed, both it and its feminine form, Allat, are found not infrequently among the theophorous names in inscriptions from North Africa" (Islam: Muhammad, and His Religion, New York: The Liberal Arts Press, 1958, p. 85).
The word "Allah" comes from the compound Arabic word, al-ilah. Al is the definite article "the" and ilah is an Arabic word for "god." It is not a foreign word. It is not even the Syriac word for God. It is pure Arabic. (There is an interesting discussion of the origins of Allah, in "Arabic Lexicographical Miscellanies" by J. Blau in the Journal of Semitic Studies, Vol. XVII, #2, 1972, pp. 173-190).
Neither is Allah a Hebrew or Greek word for God as found in the Bible. 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).