a weapon that discharges a missile at high velocity (especially from a metal tube or barrel)large but transportable armamenta person who shoots a gun (as regards their ability)a professional killer who uses a guna hand-operated pump that resembles a revolver; forces grease into parts of a machinea pedal that controls the throttle valve; "he stepped on the gas"
the discharge of a firearm as signal or as a salute in military ceremonies; "two runners started before the gun" "a twenty gun salute"