What is "shemhamphorasch"

The Shemhamphorasch (alternatively Shem ha-Mephorash or Schemhamphoras, originally ) is an originally Tannaitic term describing a hidden name of God in Kabbalah (including Christian and Hermetic variants), and in some more mainstream Jewish discourses. It is composed of either 4, 12, 22, 42, or 72 letters (or triads of letters), the last version being the most common.