entropy /ˈɛntrəpi/
n. 1.
Physics a thermodynamic quantity representing the unavailability of a system’s thermal energy for conversion into mechanical work, often interpreted as the degree of disorder or randomness in the system.
2.
lack of order or predictability; gradual decline into disorder.
3.
(in information theory) a logarithmic measure of the rate of transfer of information in a particular message or language.