Ayin, nothing, is used in Kabbalah of the highest aspect of God, beyond any something. The Maggid of Mezeritch taught that the worshipper must turn from yesh, something, to ayin, seeing oneself as nothing, so that the divine flow can renew creation through one.
Ayin
Nothingness: in Kabbalah and Hasidism, the divine nothing from which all things come, and to which the soul returns.
Also: Ayin