Compensator
A muzzle device that vents gas upward to counter muzzle rise during firing, distinct from a brake aimed at fighting rearward recoil.
A compensator is a muzzle-device with ports cut so that escaping gas is directed upward, producing a downward reaction at the muzzle that counters muzzle-rise. By holding the muzzle flatter as the shot breaks, it helps the shooter stay on target through recoil and recover the sight picture faster for a follow-up shot.
The distinction from a muzzle-brake is one of emphasis: a brake vents gas rearward and to the sides to reduce felt recoil straight back, while a compensator concentrates on attitude control to keep the bore from climbing. Many real-world devices blend both functions, but the term compensator specifically describes the rise-fighting role.