Thoth (his name in the Greek language) was the Egyptian god of the moon (lunar deity), wisdom, writing, magic, and measurement of time, among other things. The original pronunciation of his name was approximately Tee-HOW-ti. He was a son of either Re or Set. Thoth was a close companion of Astennu, which also referred to Thoth himself, occasionally. He had a daughter named Seshat.
Thoth was known as a reasonable mediator. He supported Horus vs. Seth and mediated between Tefnut and Re. In Duat, the underworld, he helped Osiris judge the souls of the dead. He also convinced Hathor (alternatively: Tefnut) to return to Egypt after she fled, pursuant to an argument with Ra (alternatively: Shu)
Thoth was credited by the ancient Egyptians as the inventor of writing, and of the 365-day calendar. He was usually depicted with the head of an ibis (whose beak looks like a crescent moon) or of a baboon (a nocturnal animal that has many similarities to humanity).
During the late period of Egyptian history a cult of Thoth gained prominence, and millions of ibises were mummified and buried in his honour.
Alternative: Thot, Djeheuty (Egypt), Tehuti, Tahuti, Zehuti
In modern times, the Tarot is sometimes referred to as The book of Thoth, as it is believed to contain ancient knowledge originally brought to man by this deity. There is also a specific tarot deck by Aleister Crowley and Lady Frieda Harris called the Thoth Deck. See Thoth Tarot.