Shem HaMephorash (Hebrew: שֵׁם הַמְּפֹרָשׁ Šēm hamMəfōrāš, also Shem ha-Mephorash), meaning "the explicit name," was originally a Tannaitic term for the Tetragrammaton.[1] 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.[2]
Early sources, from the Mishnah to the Geonim, only use "Shem haMephorash" to refer to the four-letter Tetragrammaton.[1][3]