On a firearm or other tools, a pistol grip is a distinctly protruded handle underneath the main mechanism, to be held by the user's hand at a more vertical (and thus more ergonomic) angle, similar to how one would hold a conventional pistol.
In firearms, the pistol grip is located behind the trigger and generally held by the hand that operates the trigger. Rifles and shotguns without pistol grips are generally referred to as having "straight" or "upland" (shotguns only) style stocks. Some firearms, starting from a 1840s Belgian carbine, and some automatic weapons in the 20th century (e. g., Chauchat MG, Thompson submachine gun, AK-47 assault rifle), have a second frontal pistol grip (or foregrip) on the firearm's fore-end to be used by the support hand for better stability in operation.