Chaos

Chaos is, by one definition, the absense of Order in the universe. Other people, perhaps incorrectly and certainly paradoxically, use the word interchangably with entropy, which will eventually result in the heat-death of the universe, a state of absolute order.

Chaos is also used metonymically by various people to mean Chaos magic, Chaos Math, or Discordianism. None of which are identical. (Unless of course they are.)