Pistol Grip
A grip extending vertically from the receiver, gripped like a pistol.
A pistol grip is the upright handle on a rifle (AR-15, AK, etc.) or shotgun that lets the shooter wrap their strong hand around it like a pistol’s grip. Several US states regulate pistol-gripped long guns under “assault weapon” laws, treating the feature as a regulated configuration element. On handguns, pistol grip and grip are synonyms.