Definition of "Chaos"

(Greek mythology) In Greek mythology, the primordial state of disorder that exists before the creation of the world, or the first being or deity to exist.

(astronomy) A planetoid and cubewano orbiting in the Kuiper belt.  examples

(fantasy, science fiction) In the Warhammer franchise, a demonic antagonist that sends demons, monsters, warriors, and beasts to wage war on the games' setting.  examples