The word means “self being”. It means that God is God. That he is not derived from anything else nor is there anything apart from him in terms of which he can be judged. There is no idea, for example, of the good or of justice apart from God whereby God can be judged. All things were made by him and without him was not anything made that was made. So that all creation is the handiwork of God, all things visible and invisible are his creation.