tzimtzum or tsimtsum “contraction/constriction/condensation” is a term used in the Lurianic Kabbalah to explain Isaac Luria’s doctrine that God began the process of creation by “contracting” his Ohr Ein Sof (infinite light) in order to allow for a “conceptual space” in which finite and seemingly independent realms could exist.
This primordial initial contraction, forming a “vacant space” 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.
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” (“the Place”) in Rabbinic literature (“He is the Place of the World, but the World is not His Place”).