Question: is a tommy gun a sub machine gun

Answer: Yes, The Thompson submachine gun is an American submachine gun, invented by John T. Thompson in 1918, that became infamous during the Prohibition era, becoming a signature weapon of various police 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'', ``Annihilator'', ``Chicago Typewriter'', ``Chicago Piano'', ``Chicago Style'', ``Chicago Organ Grinder'', ``Trench Broom'', ``Trench Sweeper'', ``The Chopper'', and simply ``The Thompson''.