Hermetic

-al , hėr-met′ik, -al, adj. belonging in any way to the the beliefs current in the Middle Ages under the name of Hermes , the Thrice Great: belonging to magic or alchemy, magical: perfectly close.— adv. Hermet′ically .— n.pl. Hermet′ics , the philosophy wrapped up in the Hermetic books, esoteric science: alchemy.— Hermetically sealed , closed completely, said of a gla ve el, the opening of which is closed by melting the gla . [From Hermēs Trismegistos , Hermes 'the thrice-greatest,' the Greek name for the Egyptian god Thoth, who was god of science, esp. alchemy.]