Use 'hermetically' to describe something sealed so well that no air can enter or escape. The laboratory samples were stored in hermetically sealed containers.
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Complete Isolation
'Hermetically' implies no outside elements can penetrate the barrier, like a perfect bubble. The rare documents were kept in a hermetically controlled environment.
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Technical Contexts
Often used in scientific or technical contexts where precise conditions are essential. Food safety requires certain products to be hermetically packaged.