The Browning Hi-Power is a single-action, 9 mm semi-automatic handgun. It is based on a design by American firearms inventor John Browning, and completed by Dieudonné Saive at Fabrique Nationale (FN) of Herstal, Belgium.
The Hi-Power name alluded to the 13-round magazine capacity; almost twice that of contemporary designs such as the Luger or Mauser 1910. The pistol is often referred to as an HP (for 'Hi-Power' or 'High-Power') or as a GP (for the French term, 'Grande Puissance').
Standard Hi-Powers are based on a single-action design. Unlike modern double-action semi-automatic pistols, the Hi-Power's trigger is not connected to the hammer. If a double-action pistol is carried with the hammer down with a round in the chamber and a loaded magazine installed, the shooter may fire the pistol by simply pulling the trigger. In contrast, a single-action pistol must be cocked manually before the first shot, either by thumbing the hammer back, or by pulling the slide to the rear and releasing it. In common with the M1911, the Hi-Power is therefore typically carried with the hammer cocked and the safety catch on.