What is the meaning of Hermetic?

Pertaining to ancient Greek Olympian God Hermes

Pertaining to Hermes Trismegistus or the writings attributed to him.

One who follows/worships Hermes.

Pertaining to alchemy or occult practices; magical, alchemical.

Hermetically sealed.

Isolated, away from outside influence.

Obsolete form of ermetic.

Source: wiktionary.org