See more synonyms for seal on
  1. an embossed emblem, figure, symbol, word, letter, etc., used as attestation or evidence of authenticity.
  2. a stamp, medallion, ring, etc., engraved with such a device, for impressing paper, wax, lead, or the like: The king took the seal from his finger and applied it to the document.
  3. the impression so obtained: It was unmistakably the royal seal on the document.
  4. a mark or symbol attached to a legal document and imparting a formal character to it, originally wax with an impression.
  5. a piece of wax or similar adhesive substance so attached to an envelope, folded document, etc., that it must be broken when the object is opened, insuring that the contents have not been tampered with or altered.
  6. anything that tightly or completely closes or secures a thing, as closures or fastenings for doors and railroad cars, adhesive stamps and tapes used to secure the flap of an envelope, etc.
  7. something that keeps a thing secret: Her vow was the seal that kept her silent.
  8. a decorative stamp, especially as given to contributors to a charitable fund: a Christmas seal.
  9. a mark, sign, symbol, or the like, serving as visible evidence of something.
  10. anything that serves as assurance, confirmation, or bond: She gave the plan her seal of approval.
  11. Plumbing.
    1. a small amount of water held by a trap to exclude foul gases from a sewer or the like.
    2. the depth of the part of the water that actually excludes the gases.
  12. the seals, British. the tokens or signs of public office.
verb (used with object)
  1. to affix a seal to in authorization, testimony, etc.
  2. to assure, confirm, or bind with or as if with a seal: They sealed the bargain with a handshake.
  3. to impress a seal upon as evidence of legal or standard exactness, measure, quality, etc.
  4. to close by any form of fastening that must be broken before access can be gained.
  5. to fasten or close tightly by or as if by a seal: She was sealing envelopes. My lips are sealed.
  6. to decide irrevocably: to seal someone's fate.
  7. to grant under one's seal or authority, as a pardon.
  8. Mormon Church. to make (a marriage or adoption) forever binding; solemnize.
  9. Electricity. to bring (a plug and jack or socket) into locked or fully aligned position.
Verb Phrases
  1. seal off,
    1. to close hermetically: to seal off a jar.
    2. to block (an entrance, area, etc.) completely so as to prevent escape or entrance: The police sealed off the area after the bomb threat was received.
  1. set one's seal to, to give one's approval to; authorize; endorse: Both families have set their seal to the marriage.

Origin of seal

1175–1225; (noun) Middle English seel, seil(e), seale mark on a document, token < Old French seel (French sceau) < Late Latin *sigellum, Latin sigillum, diminutive of signum sign; replacing Middle English seil, Old English (in)segel seal < Late Latin, as above; (v.) sealen, seilen < Old French seeler, seieler, derivative of seel
Related formsseal·a·ble, adjectivere·seal·a·ble, adjective
Can be confusedceiling sealing Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for seal off


  1. a device impressed on a piece of wax, moist clay, etc, fixed to a letter, document, etc, as a mark of authentication
  2. a stamp, ring, etc, engraved with a device to form such an impression
  3. a substance, esp wax, so placed over an envelope, document, etc, that it must be broken before the object can be opened or used
  4. any substance or device used to close or fasten tightly
  5. a material, such as putty or cement, that is used to close an opening to prevent the passage of air, water, etc
  6. a small amount of water contained in the trap of a drain to prevent the passage of foul smells
  7. an agent or device for keeping something hidden or secret
  8. anything that gives a pledge or confirmation
  9. a decorative stamp often sold in aid of charity
  10. Also called: seal of confession RC Church the obligation never to reveal anything said by a penitent in confession
  11. set one's seal on or set one's seal to
    1. to mark with one's sign or seal
    2. to endorse
verb (tr)
  1. to affix a seal to, as proof of authenticity
  2. to stamp with or as if with a seal
  3. to approve or authorize
  4. (sometimes foll by up) to close or secure with or as if with a sealto seal one's lips; seal up a letter
  5. (foll by off) to enclose (a place) with a fence, wall, etc
  6. to decide irrevocably
  7. Mormon Church to make (a marriage or adoption) perpetually binding
  8. to subject (the outside of meat, etc) to fierce heat so as to retain the juices during cooking
  9. to close tightly so as to render airtight or watertight
  10. to paint (a porous material) with a nonporous coating
  11. Australian and NZ to consolidate (a road surface) with bitumen, tar, etc
Derived Formssealable, adjective

Word Origin for seal

C13 seel, from Old French, from Latin sigillum little figure, from signum a sign


  1. any pinniped mammal of the families Otariidae (eared seals) and Phocidae (earless seals) that are aquatic but come on shore to breedSee eared seal, earless seal Related adjectives: otarid, phocine
  2. any earless seal (family Phocidae), esp the common or harbour seal or the grey seal (Halichoerus grypus)
  3. sealskin
  1. (intr) to hunt for seals
Derived Formsseal-like, adjective

Word Origin for seal

Old English seolh; related to Old Norse selr, Old High German selah, Old Irish selige tortoise
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for seal off



"design stamped on wax," especially one attached to a document as evidence of authenticity, c.1200, from Old French seel "seal on a letter" (Modern French sceau), from Vulgar Latin *sigellum (source of Italian suggello, Spanish sello; also Old Frisian and Middle High German sigel, German Siegel), from Latin sigillum "small picture, engraved figure, seal," diminutive of signum "mark, token" (see sign (n.)). An earlier borrowing directly from Latin is represented by Old English insigel. Technical use, "what prevents the escape of a gas or liquid" is from 1853.



fish-eating mammal with flippers, Old English seolh "seal," from Proto-Germanic *selkhaz (cf. Old Norse selr, Swedish sjöl, Danish sæl, Middle Low German sel, Middle Dutch seel, Old High German selah), of unknown origin, perhaps a borrowing from Finnic. Seal point "dark brown marking on a Siamese cat" is recorded from 1934, from the dark brown color of seal fur; cf. seal brown "rich, dark brown color," by 1875. Old English seolhbæð, literally "seal's bath," was an Anglo-Saxon kenning for "the sea."



"to fasten with (or as with) a seal," c.1200, from seal (n.1). Meaning "to place a seal on (a document)" is recorded from mid-14c.; hence "to conclude, ratify, render official" (late 15c.). Sense of "to close up with wax, lead, cement, etc." is attested from 1660s, from the notion of wax seals on envelopes. In reference to the actions of wood-coatings, 1940. Related: Sealed; sealing. Sealing-wax is attested from c.1300. To seal (one's) fate (1799) probably reflects the notion of a seal on an execution warrant.

Online Etymology Dictionary, © 2010 Douglas Harper

seal off in Science


  1. Any of various aquatic carnivorous mammals of the families Phocidae and Otariidae, having a sleek, torpedo-shaped body and limbs that are modified into paddlelike flippers. Seals live chiefly in the Northern Hemisphere and, like walruses, are pinnipeds.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Idioms and Phrases with seal off

seal off

Also, seal up. Close tightly or barricade to prevent entry or exit. For example, We're sealing off the unused wing of the building, or The jar is tightly sealed up. Dating from the first half of the 1900s, this idiom uses seal in the sense of “close securely,” as one used to do with a seal of wax.


In addition to the idioms beginning with seal

  • seal of approval
  • seal off
  • seal one's fate

also see:

  • lips are sealed
  • set one's seal on
  • signed, sealed and delivered
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.