Emanation is a vibration that is issued or comes from a single source. In mysticism the world is sometimes considered to be the most physical, dense, or “gross” emanation of the godhead. The mystical cosmologies of the Kabbalah, Gnosticism and Neoplatonism conceived the Creation process in this way.
In the Kabbalah, for example, there are ten emanations, or sephiroth, fcrom Air Soph Aur – the limitless light. These emanations are manifested through Four Worlds, which were successively more dense. They were named Atziluth, Briah, Yetzirah, and Assiah, respectively. A.G.H.
Source: 62, 77.