Firing mechanism in the context of "Stock (gun)"

A gunstock or often simply stock, the back portion of which is also known as a shoulder stock, a buttstock, or simply a butt, is a part of a long gun that provides structural support, to which the barrel, action, and firing mechanism are attached. The stock also provides a means for the shooter to firmly brace the gun and easily aim with stability by being held against the user's shoulder when shooting the gun, and helps to counter muzzle rise by transmitting recoil straight into the shooter's body.

The tiller of a crossbow is functionally the equivalent of the stock on a gun.

The lock of a firearm is the mechanism used to initiate firing. It is generally used as a historical term, referring to such mechanisms used in muzzle-loading and early breech-loading firearms, as modern firearms uniformly fire by use of a firing pin to strike the rear of a cartridge. Side-lock refers to the type of construction, in which the individual components of the mechanism are mounted either side of a single plate. The assembly is then mounted to the stock on the side of the firearm. In modern firearm designs, the mechanism to initiate firing is generally constructed within the frame or receiver of the firearm and is referred to as the firing or trigger mechanism.