Forend
The portion of a long gun's stock forward of the trigger guard, gripped by the support hand.
Also: forearm, handguard
The forend (or forearm or handguard) is the front portion of a rifle or shotgun stock that the support hand grips. On AR-pattern rifles, the forend is often a free-floating handguard with M-LOK or Picatinny mounting slots. On pump-action shotguns, the forend slides as part of the action.