The Colt Single Action Army is a single-action revolver handgun. It was designed for the U.S. government service revolver trials of 1872 by Colt's Patent Firearms Manufacturing Company and was adopted as the standard-issued pistol of the U.S. Army from 1873 to 1892.

A trigger is a mechanism that actuates the function of a ranged weapon such as a firearm, airgun, crossbow, or speargun. The word may also be used to describe a switch that initiates the operation of other non-shooting devices such as a trap, a power tool, or a quick release. A small amount of energy applied to the trigger leads to the release of much more energy.