I think one's definition of God depends upon the point one's mind is in evolution.
At my present point, the following two definitions satisfy my need to know.
1) The Trans-Himalayan: What the scientist calls energy, the religious man calls God, and yet the two are one. The life of God, his energy and vitality are found in every atom. His essence indwell all forms.
2)That deeply emotional conviction of the presence of a superior reasoning power which is revealed in the incomprehensible Universe forms my idea of God. (Albert Einstein)