The concept of entropy was introduced into the study of thermodynamics by Rudolph Clausius in 1856 to give a quantitative basis for the second law. Entropy measures how much thermal energy or heat per temperature. Entropy always entails disorganization, disorder, dissipation, or diffusion. It shows up frequently as a measure of the degree of organization of a system.
For example, Light a match in a closed, calm room. Observe the smoke. The smoke will always expand and spread out, becoming more disordered, never becoming more concentrated or organized on its own. Man-made things (cups, chairs, computers) are less entropic.