Allah and its use in the Arabic language
The term Allah (Arabic: ????, Allah) is the standard Arabic word for God and is most likely derived from a contraction of the Arabic article al- and ilah, which means "deity or god" to al-lah meaning "the [sole] deity, God." There is another theory that traces the etymology of the word to the Aramaic Alaha.
Today's Arabic speakers from all religious backgrounds (Muslims, Christians, and Jews) use the word Allah to mean God. In pre-Islamic Arabia, pagan Meccans used Allah as a reference to the creator-god, possibly the supreme deity.
The first-known translation of the Bible into Arabic, which took place in the 9th century, uses the word Allah for God (1). In fact, Arab Christians were using the word Allah for God prior to the dawn of Islam, and it is important to note that they were using it in place of Elohim, but not in place of Yahweh. That means Allah is a generic word for God, but not the personal name of God. (Radical Muslims in the West claim that Allah, not Yahweh or any other Bible name, is the name of the one true God.)
As an example closer to home, Christians and non-Christians alike use the word God in English, but that does not make the God of the Bible the same as the god of the Mormons, Jehovah’s Witnesses, or others. Another example is that when irreverent people use the expression “Oh my God!” in their day-to-day communications, they are not referring to the God of the Bible when they invoke that term.
When the prophet of Islam started his ministry in Mecca, he considered at one point uniting the Arabs under a different name for God. His favorite was Al-Rahman but he chose Allah to name his god. After the spread of Islam in the Middle East, Arab Christians continued to use word Allah since it did not have any negative connotations to them personally. Once again, it is important to understand that both before and after Muhammad, the Allah of the Arabs was not the Allah of the Arab Christians.
Today, Muslims claim they worship the same God as Christians and Jews. In fact, the Islamic propaganda machine in the West is attempting to change our English vocabulary to accommodate Islamic beliefs. Before tackling that topic, however, I’d like to address a controversial subject that is gaining momentum among American Christians, and is greatly harming the propagation of the Gospel among Muslims: the notion that Allah was the name for a pagan moon god of pre-Islamic time. I believe this theory is greatly misunderstood by American Evangelicals, and is being mixed up with the Islamic push to use Allah in our vocabulary as His name or as an alternative to the word God.