1. measure of disorder: a measure of the disorder that exists in a system
2. physics measure of unavailable energy: a measure of the energy in a system or process that is unavailable to do work. In a reversible thermodynamic process, entropy is expressed as the heat absorbed or emitted divided by the absolute temperature. Symbol S
3. communication measure of efficiency: a measure of the random errors noise occurring in the transmission of signals, and from this a measure of the efficiency of transmission systems
