/ hɜːˈmetɪk; NAmE hɜːrˈm-/ adjective
1.
( technical ) tightly closed so that no air can escape or enter
SYN airtight
2.
( formal , disapproving ) closed and difficult to become a part of :
the strange, hermetic world of the theatre
► her·met·ic·al·ly / -kli; NAmE / adverb :
a hermetically sealed container
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WORD ORIGIN
mid 17th cent. (in sense 2): from modern Latin hermeticus , from Hermes (the messenger of the gods in Greek mythology), identified with Thoth (a moon god in Egyptian mythology), regarded as the founder of alchemy and astrology.