Hermeticism or Hermetism is a philosophical and religious system based on the purported teachings of Hermes Trismegistus. These teachings are contained in the various writings attributed to Hermes, which were produced over a period spanning many centuries and may be very different in content and scope.
The Magician, from the Rider–Waite tarot deck, is often thought to display the Hermetic concept of "as above, so below".
Hermes Trismegistus is a legendary Hellenistic period figure that originated as a syncretic combination of the Greek god Hermes and the Egyptian god Thoth. He is the purported author of the Hermetica, a widely diverse series of ancient and medieval pseudepigraphica that lay the basis of various philosophical systems known as Hermeticism.
Hermes depicted with a kerykeion (caduceus), a kithara, a petasos (round hat) and a traveler's cloak, Vatican Museums
Thoout, Thoth Deux fois Grand, le Second Hermès, N372.2A, Brooklyn Museum
Hermes Trismegistus, floor mosaic in the Cathedral of Siena
Pages from a 14th-century Arabic manuscript of the Cyranides, a text attributed to Hermes Trismegistus