Shem HaMephorash

Shem HaMephorash (Hebrew: שֵׁם הַמְּפֹרָשׁ Šēm hamMəfōrāš, also Shem ha-Mephorash), meaning "the explicit name", was originally a Tannaitic term for the Tetragrammaton. In Kabbalah, it may refer to a name of God composed of either 4, 12, 22, 42, or 72 letters (or triads of letters), the latter version being the most common.

Early sources, from the Mishnah to the Geonim, only use "Shem haMephorash" to refer to the four-letter Tetragrammaton.