(1) The discharge of a firearm as signal or as a salute in military ceremonies
"Two runners started before the gun"
"A twenty gun salute"
(2) A pedal that controls the throttle valve
"He stepped on the gas"
(3) Large but transportable armament
(4) A hand-operated pump that resembles a revolver; forces grease into parts of a machine
(5) A weapon that discharges a missile at high velocity (especially from a metal tube or barrel)
(6) A professional killer who uses a gun
(7) A person who shoots a gun (as regards their ability)
(8) Shoot with a gun