The handle of a handgun or the butt end of a rifle or shotgun or part of the support of a machine gun or artillery gun WordNet 3.0 & Open English WordNet

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. Wikipedia

A part of a gun Wikipedia Disambiguation

A part of a gun which interfaces with the shoulder or hand Wikipedia Disambiguation

Structural component of a long gun Wikidata

The stock in a firearm located in the rear of the firing mechanism where one's shoulder is held when shooting. Wiktionary

The rear part of a musket, rifle or shotgun which is pressed into the shoulder. Wiktionary

The part of a rifle or shotgun that rests against the shooter's shoulder. Wiktionary