Chaos (pronounced /ˈkeɪ.ɒs/; derived from the Ancient Greek Χάος, Chaos) typically means a state lacking order or predictability. In ancient Greece, it first meant the initial state of the universe, and, by extension, space, darkness, or an abyss (the antithetical, or possibly complementary, concept was cosmos), but later uses of the term by philosophers varied over time. In modern English, the word is used in classical studies with the original meaning; in mathematics and science to refer to a very specific kind of unpredictability; and informally to mean a state of confusion. In philosophy, and in popular culture, the word can occur with all three meanings. .
