Refers to a short-barreled firearm, typically a handgun. The term is somewhat dated; modern Japanese more commonly uses ピストル or 拳銃.
In period dramas, there are scenes where a samurai aims a pistol.
Compound of 短 (short) and 筒 (tube, cylinder), referring to a short-barreled firearm. The exact historical origin is uncertain, but it likely arose as a descriptive term for early handguns.