adj of, pertaining to, or taught by, hermes trismegistus; as, hermetic philosophy. hence: alchemical; chemic.
2. hermetical ·adj 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.
3. hermetical ·adj 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.