1.(communication theory) a numerical measure of the uncertainty of an outcome - the signal contained thousands of bits of information • Syn: information, selective information • Topics: communications, communication theory • Hypernyms: information measure 2.(thermodynamics) a thermodynamic quantity representing the amount of energy in a system that is no longer available for doing mechanical work - entropy increases as matter and energy in the universe degrade to an ultimate state of inert uniformity • Syn: randomness, S • Topics: thermodynamics • Hypernyms: physical property • Hyponyms: conformational entropy