The name of God in Islam results from a contraction of the Arab term Al-Jlâh which means the single one.
Allah is only God. It is what a verse of Coran (VII.157) affirms which constitutes the chahâda, the act of faith of any Moslem: “There is not other God that Allah, and Mahomet is its prophet.”
He is also One, as the sourate 112 affirms it: “He is God One (ahad), impenetrable God and without crack (samad), no one is not equal to him. He did not generate and was not generated <… >.”
Allah is thus primarily different from Trinitarian God of the Christians, but near of biblical Adonaï chad.
He is also transcendent - “No one is not equal to Him” -, eternal and the Almighty. He very created, by an act of pure good pleasure: “Him, he is not asked for reason of what he did”, “Not a sheet of tree does not fall without He knowing it” (VI.59).
Unknowable, being represented it would not know: “Allah is it beyond all.” This faith, which proclaims only Allahu Akbar (God is tall), should give place to no theology.
However, Moslem piety expresses, in a chain with 99 grains (subha) - “hundred minus one, because, the Odd one, likes to Him to be indicated by these names one by one” - 99 “beautiful names” of Allah: the Benefactor, it Sympathizing, the King, the Saint, Peace, the Believer, the Vigilant one, the Powerful one, the Lenient one, the Benevolent one, the Wise one, Very the Magnet, the Alive one, etc the last name is the name of Allah.
Though “Lord of the decree”, “Sovereign of the Day of the Judgment” which “will forgive what He will want with those that He will want”, Allah is often called upon like “That which makes mercy, the Merciful one” (in Fâtiha, prayer of opening).