the quality of lacking any predictable order or plan
(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"
an unknown and unpredictable phenomenon that causes an event to result one way rather than another; "bad luck caused his downfall"; "we ran into each other by pure chance"
an unknown and unpredictable phenomenon that leads to a favorable outcome; "it was my good luck to be there"; "they say luck is a lady"; "it was as if fortune guided his hand"