\Her*met"ic\, Hermetical \Her*met"ic*al\, a. [F.
herm['e]tique. See Note under {Hermes}, 1.]
1. Of, pertaining to, or taught by, Hermes Trismegistus; as,
   hermetic philosophy. Hence: Alchemical; chemic.
   ``Delusions of the hermetic art.'' --Burke.
         The alchemists, as the people were called who tried
         to make gold, considered themselves followers of
         Hermes, and often called themselves Hermetic
         philosophers.                         --A. B.
                                               Buckley.
2. Of or pertaining to the system which explains the causes
   of diseases and the operations of medicine on the
   principles of the hermetic philosophy, and which made much
   use, as a remedy, of an alkali and an acid; as, hermetic
   medicine.
3. Made perfectly close or air-tight by fusion, so that no
   gas or spirit can enter or escape; as, an hermetic seal.
   See Note under {Hermetically}.
{Hermetic art}, alchemy.
{Hermetic books}.
   (a) Books of the Egyptians, which treat of astrology.
   (b) Books which treat of universal principles, of the
       nature and orders of celestial beings, of medicine,
       and other topics.