Atzmus or Atzmut (עצמות from the Hebrew עצם etzem) is the descriptive term referred to in Kabbalah, and explored in Hasidic thought, for the divine essence.
Classical Kabbalah predominantly refers to the Godhead in Judaism with its designated term "Ein Sof" ("No end"-Infinite). Reference to atzmus is usually restricted in Kabbalistic theory to discussion whether "Ein Sof" represents the ultimate divine being in itself, or to God as first cause of creation.