There is only one god, but not in the sense of an object with godlike qualities. God is one; meaning the only interface all must implement and obey. Thus "La ilaha illallah!": There is no (external/outside/extra) god, but Al-ilah (the-God) within.
Allah is not an object, but an interface which every possibility must implement to be. To be what? To be itself: Methods are defined by the interface, but they are given meaning by the being. Thus the outcome is always Him, but at the same time not Himself.
Although name it 'red' or 'green', is a color on itself, it doesn't define the concept of color alone. Because although they are both colors, neither is the COLOR itself. Therefore, as there is none but Him, there is none equivalent to Him.
He is the Definer. He defines your boundaries; what you can and you can't do. He gives you life and you give Him meaning with it. Then behold! You become the definer; definition of life.
So how do you define Him? That is the only question. Because what you believe, you define; what you define, you experience.