Adi (Skt., 'first') is a Hindu, Buddhist, and Theosophical term meaning the first part of reality. It has to do with the first cause or even Adi-Ananta—at least as unity of infinity (as Plotinus and others say) emanating the first finite one. This is called Brahm (in Hinduism) and Adi-Buddha, and Theosophy also says it has to do with the Divine Monad, e.g. Logos.