Allah - This is an Arabic word which means "the One True God." Most Muslims in the West use Allah and God interchangeably.

Allah ( allahu) is the Arabic word for "God". A related Arabic term, Allahumma, corresponds to the Hebrew divine name of Elohim; both being ultimately derived from Proto-Semitic ?il, c.f. Hebrew El). The word Allah is traditionally used by Muslims, but it is not used in Islam exclusively; Arab Christians and Arab Jews also use it to refer to the monotheist deity. (wikipedia)

The supreme God of all creation. He is known as "God" or "Father" to the Christians, and as "El" or "Yahweh" to the Jews. This assumes the Qur'an is true in saying that "our God is the same as your God". Christians and Jews might not always be inclined to agree with this. See the article "Is Allah the God of the Bible? (Answering Islam )

The Arabic term for God. The word was used for local gods in Arabia before Muhammad began to use it for the one God that revealed His messages to him. Arab Christians and Jews also use the term. Arabs frequently use the word inshallah, meaning "if God wills," which suggests that whatever happens in life will be a result of God's will. (Israel Project)