A news leak is a disclosure of embargoed information in advance of its official release, or the unsanctioned release of confidential information.

Leaks are often made by employees of an organization who happened to have access to interesting information but who are not officially authorized to disclose it to the press. They may believe that doing so is in the public interest due to the need for speedy publication, because it otherwise would not have been able to be made public, or simply as self-promotion, to elevate the leaker as a person of importance. Leaks can be intentional or unintentional. A leaker may be doing the journalist a personal favor (possibly in exchange for future cooperation), or simply wishes to disseminate secret information in order to affect the news. The latter type of leak is often made anonymously.

Sometimes partial information is released to the media off the record in advance of a press release to "prepare" the press or the public for the official announcement. This may also be intended to allow journalists more time to prepare more extensive coverage, which can then be published immediately after the official release. This technique is designed to maximize the impact of the announcement. It might be considered an element of political 'spin', or news management.

News is the communication of selected information on current events which is presented by print, broadcast, Internet, or word of mouth to a third-party or mass audience.

One theory claims that the English word "news" developed in the 14th century as a special use of the plural form of "new". In Middle English, the equivalent word was newes, like the French nouvelles and the German neues. Similar developments are found in the Slavic languages – the Czech and Slovak noviny (from nový, "new"), the cognate Polish nowiny and Russian novosti – and in the Celtic languages: the Welsh newyddion (from newydd) and the Cornish nowodhow (from nowydh).

Before the invention of newspapers in the early 17th century, official government bulletins and edicts were circulated at times in some centralized empires.

The first documented use of an organized courier service for the diffusion of written documents is in Egypt, where Pharaohs used couriers for the diffusion of their decrees in the territory of the State (2400 BC). This practice almost certainly has roots in the much older practice of oral messaging and may have been built on a pre-existing infrastructure.

Usually unintended and therefore undesired, a leak is a way (usually an opening) for fluid to escape a container or fluid-containing system, such as a tank or a ship's hull, through which the contents of the container can escape or outside matter can enter the container. The word "leak" is also used as a verb; matter going through the opening is said to leak. The entry, exit, or exchange of matter through the leak is called leakage, the subject of another disambiguation article. The matter leaking in or out can be gas, liquid, a highly viscous paste, or even a solid such as a powdered or granular solid or other solid particles. A leak can be between two (or more) fluid-containing systems, allowing transfer of matter from either system to the other, or even an exchange of matter between them. Leakage of matter into a container or other system could be called inleakage. Leakage of matter out of a container or other system could be called outleakage. The presence of a leak does not necessarily mean there is always leakage of matter; it just implies there could be leakage through the opening. If the container or system is empty in an empty environment, there is no leakage at that time. Sometimes the word "leak" is used to refer to leakage in a certain situation, for example the passing or making public of secret information.