hermetic

UK: /hɜːˈmɛtɪk/ US: /hɝˈmɛtɪk/ ,(hûr met′ik)

WordReference Random House Learner's Dictionary of American English © 2026

her•met•ic /hɜrˈmɛtɪk/  also herˈmet•i•cal, adj. 

1. made, sealed, or closed so tightly that no air can escape.

her•met•i•cal•ly, adv. 

WordReference Random House Unabridged Dictionary of American English © 2026

her•met•ic  (hûr met′ik), adj. 

1. made airtight by fusion or sealing.
2. not affected by outward influence or power;
   isolated.
3. Mythology (sometimes cap.) of, pertaining to, or characteristic of occult science, esp. alchemy.
4. (cap.) of or pertaining to Hermes Trismegistus or the writings ascribed to him.

Also, her•met′i•cal. 

• Medieval Latin hermēticus of, pertaining to Hermes Trismegistus, equivalent. to Latin Hermē(s) Hermes + -ticus -tic
• 1630–40

Collins Concise English Dictionary © HarperCollins Publishers::

hermetic / hɜːˈmɛtɪk/, hermetical adjective

1. sealed so as to be airtight
2. hidden or protected from the outside world

Etymology: 17th Century: from Medieval Latin hermēticus belonging to Hermes Trismegistus, traditionally the inventor of a magic seal

herˈmetically adverb

Collins Concise English Dictionary © HarperCollins Publishers::

Hermetic / hɜːˈmɛtɪk/ adjective

1. of or relating to Hermes Trismegistus or the writings and teachings ascribed to him
2. of or relating to ancient science, esp alchemy
3. esoteric or recondite

Etymology: see hermetic