A shot source is a device used to inject a substance into the body. The four solutions for the term 'shot source' are GUN (3 letters), SYRINGE (7 letters), HYPO (4 letters), and BBGUN (5 letters). A GUN is a weapon that fires bullets or other projectiles, usually by means of an explosive. A SYRINGE is a medical device used to inject a substance into the body. A hypo is a slang term for a SYRINGE. Finally, a BB GUN is a type of air GUN designed to shoot small metal balls.