Entropy (noun)

1. The degree of disorder or randomness in a system.
2. A measure of the amount of thermal energy unavailable for doing useful work.

Origin:

Late 19th century: from german entropie, from greek entrōpia, from entrōpe "being turned towards the inside", from en- "in" + trope "a turning".

Examples:

1. The entropy of the system increased as the particles became more disordered.
2. The entropy of the universe is constantly increasing.
3. The entropy of the gas in the cylinder decreased as it was compressed.
4. The entropy of the isolated system is conserved.
5. The entropy of the black hole is proportional to its surface area.