The term 'Tommy Gun' is a nickname for the Thompson submachine gun, which was first produced in 1921. It was designed by John T. Thompson and manufactured by the Auto-Ordnance Corporation. The Tommy Gun was used widely during the Prohibition era in the United States and was popular with law enforcement and criminals alike. The term 'STEN' is an acronym for the British company that produced the Sten submachine gun during World War II. The Sten was a simpler and cheaper alternative to the Tommy Gun and was used by British and Commonwealth forces.