The word “entropy” comes from the Greek word “entropia,” which means “a turning toward” or “transformation.” It was first introduced into the physical sciences in the mid-19th century by the German physicist Rudolf Clausius. Clausius used the term to describe the measure of the disorder or randomness of a system, which is a central concept in the second law of thermodynamics. The law observes that in an isolated system (one that is not taking in energy from the outside or giving energy to the outside), the amount of entropy, or disorder, will tend to increase over time, leading to the eventual equilibrium of the system. This foundational principle has been applied across various disciplines, including physics, chemistry, information theory, and more, to explain the direction of natural processes.