hermetic

IPA/hɜːˈmetɪk/
IPA/hɜːrˈmetɪk/

hermetic — adjective

  • hermeticpositive
  • more hermeticcomparative
  • most hermeticsuperlative

1. sealed in a way that stops air from getting in or out

1.adjectiveC2
Definition

sealed in a way that stops air from getting in or out

Example

The lab stores the powder in a hermetic glass jar with a rubber ring.

hermetic + container noun

Before shipping the coffee beans, Linh checked that each bag was hermetic.

predicative use: a bag was hermetic

Common collocations
  • hermetic seal
  • hermetic jar
  • hermetic chamber
  • hermetic packaging
Synonyms
  • airtight

    closest everyday synonym; strongly emphasizes that air cannot pass

  • sealed

    broader term that can describe something simply being closed, not necessarily perfectly airtight

Antonyms
  • leaky

    allows air or other matter to pass through

  • unsealed

    not closed securely

Grammar Patterns

hermetic container

be hermetic

Usage Note

Usually used for containers, chambers, packages, or seals where blocking air matters. It is more exact than sealed, because it stresses that air cannot pass through the closure.

Common Mistakes

This winter coat is hermetic enough for strong wind.
This container is hermetic, so no air gets in.
Hermetic is mainly used for sealed containers or spaces, not for ordinary clothing.

2. kept apart from outsiders and having very little contact or exchange with them

2.adjectiveC2
Definition

kept apart from outsiders and having very little contact or exchange with them

Example

The boarding school remained hermetic, with students rarely meeting local families.

hermetic about a group closed to outsiders

For years, the sect lived in a hermetic community high in the mountains.

Common collocations
  • hermetic community
  • hermetic culture
  • hermetic circle
  • hermetic world
Synonyms
  • insular

    emphasizes lack of interest in outside people or ideas

  • closed-off

    less formal and can apply to people as well as groups

  • isolated

    broader term that can describe physical or social separation

Antonyms
  • open

    willing to deal with or accept people and ideas from outside

  • outward-looking

    actively interested in the wider world

Grammar Patterns

hermetic community

be hermetic

Usage Note

Often used for communities, institutions, or social circles. It emphasizes separation from outsiders and outside influence, not literal lack of air or a locked physical space.

Common Mistakes

Our office is hermetic because the windows do not open.
Our office feels hermetic because nobody shares ideas with other teams.
This sense is about isolation from outsiders, not air flow.

Word family

Synonym discussion

Sense: adjective/1

For sense adjective/1, hermetic is strongest when air must not pass in either direction. Airtight is the closest everyday synonym and works for jars, rooms, or packaging. Sealed is broader: something sealed may simply be closed, and the word does not always stress perfect protection from air. Watertight focuses on blocking water rather than air, though a product can be both watertight and hermetic. Use hermetic when the quality of the seal matters, especially in labs, food storage, or engineering. You can call a lunch box airtight, but an engineer may test whether a chamber is truly hermetic.

airtight ↗sealed ↗watertight ↗

Common collocations

Adverbs

Phrases

  • remain hermetic

Etymology

GreekLate LatinFrenchEnglish

Hermetic comes from the name Hermes Trismegistus, a legendary figure linked with secret alchemical writing. English first used the word for things connected with those teachings, and the modern sense grew from the idea of an alchemist's vessel being sealed so completely that nothing from outside could get in.