General English


  • noun an animal which goes first, which leads the flock or herd


  • noun a product which sells best
  • noun an important share, one which is often bought or sold on the Stock Exchange


  • noun a person who manages or directs others



  • In a hot-air heating system, a duct that conveys hot air to an outlet.


  • A section of nonmagnetic tape, usually plastic, which is affixed to the beginning of a length of recording tape, such as a reel. A section attached at the end of a tape is called a trailer (1). Also called leader tape.
  • In computers, a record which precedes and describes other records.
  • An initial discharge which sets the path for a subsequent lightning stroke. The leader ionizes the air along its trajectory, and such a discharge may occur between a cloud and the ground, between clouds, or within the same cloud. Also called leader stroke.

Information & Library Science

  • noun in information retrieval, the data at the beginning of a machine-readable record identifying and locating the information content
  • noun a piece of blank tape at the beginning of a reel, which is fed into a machine


  • noun somebody who manages or directs others
  • noun the main barrister, usually a QC, in a team appearing for one side in a case

Media Studies

  • noun coloured, non-recordable tape used on reel-to-reel tape to indicate the beginning (green) and end (red) of a piece of audio


  • noun a commander


  • noun someone who is responsible for organising or controlling a group of people
  • noun someone such as a person, company, country or something such as a product that is the most successful of its type