A differential in a rear-drive vehicle fitted with a mechanism that limits the speed and torque differences between its two outputs. This ensures that some torque is always distributed to the wheels, even when one is on a very slippery surface.
An axle differential or central differential incorporating a locking or slip-limiting mechanism to counter wheel spin. Limited slip means that some power is always applied to each of the wheels, even when one of them is on a slippery surface like ice or mud.
A differential fitted with a mechanism that limits the speed and torque differences between two outputs so torque is always distributed evenly to both wheels, even on slippery surfaces.