adjective her·met·ic \ (ˌ)hər-ˈme-tik \
variants: or less commonly hermetical play \(ˌ)hər-ˈme-ti-kəl\
|Updated on: 27 Jul 2018

Definition of hermetic

1 often capitalized
a : of or relating to the mystical and alchemical writings or teachings arising in the first three centuries a.d. and attributed to Hermes Trismegistus
b : relating to or characterized by subjects that are mysterious and difficult to understand : relating to or characterized by occultism or abstruseness : recondite
  • a hermetic discussion
[from the belief that Hermes Trismegistus invented a magic seal to keep vessels airtight]
a : airtight
  • hermetic seal
b : impervious to external influence
  • trapped inside the hermetic military machine
  • —Jack Newfield
c : recluse, solitary
  • leads a hermetic life


play \(ˌ)hər-ˈme-ti-k(ə-)lē\ adverb

hermetic was our Word of the Day on 06/24/2016. Hear the podcast!

Examples of hermetic in a Sentence

  1. wrote hermetic poetry whose sole intended readership was himself

Recent Examples of hermetic from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'hermetic.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

hermetic Has Origins in Greek Mythology

Hermetic derives from Greek via the Medieval Latin word hermeticus. When it first entered English in the early 17th century, hermetic was associated with writings attributed to Thoth, the Egyptian god of wisdom. Thoth, whom the Greeks called Hermes Trismegistus ("thrice-great Hermes"), was believed to be the author of a number of mystical, philosophical, and alchemistic works. The obscure subject matter of these works may have made them difficult to wade through, for soon English speakers were also applying hermetic to things that were beyond ordinary human comprehension. Additionally, Hermes Trismegistus was said to have invented a magic seal that could keep vessels airtight. Hermetic thus came to mean "airtight," both literally and figuratively. These days, it can also sometimes mean "solitary."

Origin and Etymology of hermetic

Medieval Latin hermeticus, from Hermet-, Hermes Trismegistus

Other Religion (Eastern and Other) Terms

HERMETIC Defined for English Language Learners


Definition of hermetic for English Language Learners

  • : closed tightly so that no air can go in or out

Medical Dictionary


adjective her·met·ic \ (ˌ)hər-ˈmet-ik \

medical Definition of hermetic

: being airtight or impervious to air


play \-i-k(ə-)lē\ adverb

Biographical Note for hermetic

Her*mes Tris*me*gis*tus play \ˈhər-(ˌ)mēz-ˌtris-mə-ˈjis-təs\ Greek mythological character. Hermes Trismegistus was identified by the Greeks with the Egyptian god Thoth. To him was ascribed authorship of various works on astrology, magic, alchemy, and medicine. It was also believed that he had invented a magic seal to keep vessels airtight, and from his name the adjective hermetic meaning airtight was derived.

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very hard to disturb or upset

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