The Thompson submachine gun is an American submachine gun first invented by John T. Thompson in 1918 during World War I that became infamous during the Prohibition era, being a signature weapon of various organized crime syndicates in the United States. It was a common sight in the media of the time, being used by both law enforcement officers and criminals. The Thompson submachine gun was also known informally as the "Tommy Gun", "Street Sweeper", "Annihilator", "Chicago Typewriter", "Trench Broom", "Chicago Submachine", "Chicago Piano", "Chicago Style", "Chicago Organ Grinder", "Drum Gun", "the Chopper", "the Tommy Boy" or simply "the Thompson".