A revolver was a repeating firearm that has a revolving cylinder containing multiple chambers and at least one barrel for firing. The term revolver refers to a handgun, but other weapons may also have a revolving chamber. These include some models of grenade launchers, shotguns, and rifles.

The revolver allows the user to fire multiple rounds without reloading. Each time the user cocks the hammer, the cylinder revolves to align the next chamber and round with the hammer and barrel, which gives this type of firearm its name. In a single-action revolver, the user pulls the hammer back with his free hand or thumb; the trigger pull only releases the hammer. In a double-action revolver, pulling the trigger moves the hammer back, then releases it.