In Kabbalah, the Jewish mystical tradition, Ain, Ain Soph, and Ain Soph Aur are three stages in the process of creation, representing the highest and most abstract levels of divinity:
Meaning "nothing" or "nothingness," Ain represents the unknowable, unthinkable void before creation. It is the absolute absence, beyond all comprehension or description.
Translating to "without end" or "infinite," Ain Soph represents boundlessness. It is the limitless, eternal divine essence, beyond all attributes or definitions.
Meaning "limitless light," Ain Soph Aur is the first manifestation of divine will. It represents the infinite light of creation, the source from which all subsequent emanations and creations emerge.
These concepts form the foundation of Kabbalistic cosmology, describing the process by which the infinite and unknowable divine gradually manifests into the finite, knowable universe we experience.