The entropy of a system approaches a constant value as the temperature approaches absolute zero.
The third law is relatively easy to understand from a statistical point of view in which entropy is associated with disorder. As absolute zero is approached, all thermal motions cease, and any system must approach an ordered state in which the particles do not move. Hence, the entropy of a system is defined only to within an arbitrary constant and only changes in entropy have physical significance. The changes in entropy become negligibly small as absolute zero is approached.