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seal - definition and synonyms


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noun [countable] seal pronunciation in British English /siːl/
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  1. 1
    a large sea animal that eats fish and lives mainly in cold parts of the world. Seals are amphibious (=they can live both in water and on land). A young seal is called a pup.
  2. 2
    a piece of something such as wire or wax that seals a container and that you have to break before you can open the container
    1. a.
      a shaped piece of something such as rubber that closes a hole inside a machine so that air or other substances cannot get in or out

      I replaced the seal, but oil is still leaking out.

  3. 3
    a special mark that you put on something, for example a document, to show that it is legal or official

Open Dictionary


the activity of exploring abandoned buildings and other manmade structures

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