You searched for: “hermes trismegistus”
Hermes Trismegistus (s) (noun) (no plural form)
1. A name variously ascribed by Neoplatonists and others to an Egyptian priest or to the Egyptian god Thoth, to some extent identified with the Grecian Hermes: Various mystical, religious, philosophical, astrological, and alchemical writings were ascribed to Hermes Trismegistus.
2. The Hellenistic Hermes, Egyptianized through contact with the Egyptian Thoth: Trismegistos is derived from the Egyptian superlative obtained through repetition where Hermes appears as "Great, Great, Great" on the Rosetta stone; which was later simplified through the substitution of the prefix "tris" in the Roman period.

Hermes Trismegistus is said to have been the author of 42 "fundamental books" of Egyptian religion, including astrological, cosmological, geographical, medical, and pedagogic (teaching) books as well as hymns to the gods and instructions on how to worship.

—The contents of entry #2 was compiled from information located in
The Oxford Classical Dictionary edited by Simon Hornblower and Antony Spawforth;
Oxford University Press; Oxford, England; 2003; page 691.
This entry is located in the following unit: herm-, herme- (page 1)
A unit related to: “hermes trismegistus”
herm-, herme-
(Greek: Hermes, the son of Zeus and Maia, the god of commerce and messenger of the gods in Greek mythology; identified by the Romans as Mercury; however, some of the words in this unit come from Hermes tris megistos, Hermes Trismegistus, literally, "Hermes, Thrice the Greatest" referring to the Egyptian god Thoth, who was identified with the Greek god Hermes, of science and arts)