General English


  • noun the escape of liquid or gas from a sealed container, or the amount of liquid or gas that has escaped


  • A flaw or fault which allows the undesired escape of something, such as a fluid or energy. Also, the location of such a flaw or fault. Also, that which escapes. May also refer to such a flaw or fault which allows the undesired entry of something.
  • The flow of current through unwanted paths of a circuit, along the surface or through the body of a dielectric or insulator, or that which is otherwise undesired or lost. Also, the current which flows in this manner, or is lost.

Information & Library Science

  • noun a breach of security or loss of important information


  • noun the unofficial passing of information which has not yet been published, by officials, MPs or employees to newspapers, TV or radio stations, or other public forums
  • verb to make secret information public without being authorised to do so

Media Studies

  • noun an occasion when confidential information is given to the media, or the information itself
  • verb to give confidential information to the media unofficially, or become known unofficially


  • noun the unofficial passing of secret information or information which has not yet been published to newspapers or television stations


  • noun an act of urination. Usually in the expressions ‘have a leak’ or ‘take a leak’. The origin of this predictable usage may be nautical.

Origin & History of “leak”

The ultimate source of leak is probably a prehistoric Germanic *lek-, which denoted ‘deficiency’ (a variant *lak- gave English lack). It is not clear how this reached English; it could have been via Old Norse leka, or through middle Dutch lēken.