The tzimtzum or tsimtsum (Hebrew צמצום ṣimṣūm "contraction/constriction/condensation") is a term used in the Lurianic Kabbalah to explain Isaac Luria's new doctrine that God began the process of creation by "contracting" his Ein Sof (infinite) light in order to allow for a "conceptual space" in which and seemingly independent realms could exist. This primordial initial contraction, forming a Khalal/Khalal Hapanui ("vacant space", חלל הפנוי) into which new creative light could beam, is denoted by general reference to the tzimtzum. In contrast to earlier, Medieval Kabbalah, this made the first creative act a concealment/Divine exile rather than unfolding revelation. This dynamic crisis-catharsis in the Divine flow is repeated throughout the Lurianic scheme.
Because the tzimtzum results in the "empty space" in which spiritual and physical Worlds and ultimately, free will can exist, God is often referred to as "Ha-Makom" (המקום lit. "the Place", "the Omnipresent") in Rabbinic literature ("He is the Place of the World, but the World is not His Place"). In Kabbalistic interpretation, this describes the paradox of simultaneous Divine presence and absence within the vacuum and resultant Creation. Relatedly, Olam — the Hebrew for "World/Realm" — is derived from the root עלם meaning "concealment". This etymology is with the concept of Tzimtzum in that the subsequent spiritual realms and the ultimate physical universe conceal to different degrees the infinite spiritual lifeforce of creation. Their progressive diminutions of the Divine Ohr (Light) from realm to realm in creation are also referred to in the plural as secondary tzimtzumim (innumerable "condensations/veilings/constrictions" of the lifeforce). However, these subsequent concealments are found in earlier, Medieval Kabbalah. The new doctrine of Luria advanced the notion of the primordial withdrawal (a dilug - radical "leap") in order to reconcile a causal creative chain from the Infinite with finite Existence.