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.