What is limiting friction?

Limiting friction is defined as the friction generated between two static touching surfaces. The maximum friction that can be generated between two static surfaces in contact. Once a force applied to the two surfaces exceeds the boundary friction, the motion will occur.

For two dry surfaces, the boundary friction is a product of the normal reaction force and the boundary coefficient of friction. In other words, the amount of friction that can be exerted between two surfaces is limited, and if the forces acting on the body are high enough, the motion will occur. We can therefore define boundary friction as the maximum value of static friction that comes into play when the body is about to slide on the surface of another body.