An airtight seal.

simple past tense and past participle of hermetically seal

Sealed with an airtight hermetic seal.

(historical) A device used to impress a company's name and/or symbol onto a dollop of soft red wax attached to a legal instrument, where two directors or one director and the secretary could sign as witnesses, thus executing the instrument.

the official seal of a corporation

The public seal of a nation, especially the British Great Seal of the Realm; supreme authority.

A measured amount of radioisotope sealed within a protective container.

The main seal of a nation or state that symbolizes its authority, and with which official documents are stamped.

The personal seal of a English or Scottish monarch. / A document to which such a seal is attached; specifically, a warrant demanding a loan. / The position of Keeper of the Privy Seal.

The official public seal of any of several nations.