God is a word that means special effects to special people. To various Taoist or Buddhist the word is not part of their religion's glossary. To Hindus that word has a special meaning than it does to a Christian. Muslims have a different outlook and so do the Jews. So for the purpose of The Mystic Doctrines website, we require a common definition of God.
Quoting different sources from each religion before revealing the definition.
Tao, the subtle truth of the universe cannot be described, That which can be described in words is mearly a conception of the mind. Even if names and descriptions have been applied to it, the subtle truth is beyond the description. The subtle essense of the universe is elusive and evasive....It is the subtle source of the total of creation and non-creation. It existed prior to the beginning of time as the deep and subtle truth of the universe. It brings all into being.
"Present is, O monks, an unborn, unoriginated, uncreated, unformed. Were there not, O monks, this unborn, unoriginated, uncreated, unformed, present would be no escape from the world of the born, originated, created, formed. "While, O monks, there is an unborn, unoriginated, uncreated, and unformed, as a result is there an get away from the born, originated, created, formed."
Neither the multitude of gods nor huge sages identify of my origin, for I am the source of all the gods and large sages. A human who knows me as the unborn, beginning less large lord of the worlds is freed from all delusion and all problems.
Present is One, just One Supreme Being, Truth Eternal, Creator of all seen & unseen, Fearless, Without hatred, Timeless Being, Non-Incarnated, Self formed, Realized by the Grace of Guru (Perfect Master Only.)
In the beginning God created the heavens and the earth. For thus saith the Eternal that shaped the heavens; God himself that shaped the earth and made it; he hath recognized it, he created it not in vain, and he created it to be inhabited: I am the self existent One; and there is none else.
In the beginning was the Word, and the Word was with God, and the Word was God Himself. He was present initially with God. Every thing was finished and came into survival throughout Him; and without him was not one thing made that has come into organism.
You are the total survival which causes (our) transient (existences) to appear. Now, a definition of God. God is the indescribable, uncreated, self existent, eternal all knowing source of all reality and being.