1. a device impressed on a piece of wax or the like, or an impression, wafer, etc., affixed to a document as evidence of authenticity or attestation.
2. a stamp engraved with such a device.
3. an impression made with such a stamp.
4. Law a mark or symbol attached to a legal document and imparting a formal quality to it, originally defined as wax with an impression.
5. a piece of wax or similar substance, affixed to a document, an envelope, a door, etc., which cannot be opened without breaking this.
6. anything that effectively closes a thing.
7. something for keeping a thing close or secret.
8. a decorative stamp: a Christmas seal.
9. a mark or the like serving as visible evidence of something.
10. Plumbing a. a small amount of water left standing in a trap to prevent the escape of foul air from below. b. the depth of the water between the dip and the overflow of a trap.
11. a road surface of hard material, as tar, bitumen, etc.: the tar seal.
-- verb (t)
12. to affix a seal to an authorisation, confirmation, etc.
13. to approve, authorise, or confirm: to seal an agreement.
14. to impress a seal upon as an evidence of legal or standard exactness, measure, quality, etc.
15. to fasten with a seal.
16. to close by any form of fastening that must be broken before access can be had.
17. to fasten or close as if by a seal.
18. to decide irrevocably: to seal someone's fate.
19. to grant under one's seal or authority, as a pardon.
20. to surface a road with tar, bitumen, etc.
21. Mormon Church to make for ever binding, to give in marriage, or to join in family ties, according to the principle of marriage for eternity.
22. Electricity to bring (a plug and jack or socket, etc.) into locked or fully aligned position.
23. set one's seal on or set one's seal to, to approve or endorse.
24. the seals, the tokens or signs of public office.
25. under seal, (of a document) bearing a seal (def. 1).
[ME seel, from OF, from LL sigellum, replacing L sigillum ]
-- sealable, adverb