Newton's law that states that for every action there is an equal and opposite reaction

is known as Newton's third law of motion. This law explains the relationship between forces acting on two interacting objects. It states that when one object exerts a force on a second object, the second object exerts a force of equal magnitude and opposite direction back on the first object. This law is essential for understanding how forces interact in the physical world and is fundamental in the study of mechanics and dynamics.