(Sanskrit. In Tibetan, Dang-po'i sangs-rgyas) From Vajrayana Buddhism; also known as Samantabhadra/Samantabhadri or Vajradhara. Adi-Buddha, Adhi-buddha, or Adibuddha is the "Primordial Buddha," or origin of all the Buddhas. Adi-Buddha is a self-emanating, self-originating Buddha, present before anything else existed.
"The Thirteenth Aeon is Ain, Sat, the Seity. Beyond the Thirteenth Aeon is the Cosmic Common Eternal Father, and Adi-Buddha, who is the Buddha of our individual Buddha. Adhi-Buddha is the Father of our Father, but He never comes into manifestation, because He is the Unknowable Divinity. Only at the end of the mahamanvantara, after having integrated ourselves with our Father who is in secret, do we then integrate ourselves with Adhi-Buddha. This integration with Adhi-Buddha is performed in the mahapralaya, in the cosmic night and within the bosom of the Absolute Abstract Space." - Samael Aun Weor, The Gnostic Bible: The Pistis Sophia Unveiled