ch.ao/s |ˈkāˌäs|
noun

complete disorder and confusion: snow caused chaos in the region.
Physics behavior so unpredictable as to appear random, owing to great sensitivity to small changes in conditions.
• the formless matter supposed to have existed before the creation of the universe.
• (Chaos) Greek Mythology the first created being, from which came the primeval deities Gaia, Tartarus, Erebus, and Nyx.



ORIGIN late 15th cent. (denoting a gaping void or chasm, later formless primordial matter): via French and Latin from Greek khaos ‘vast chasm, void.’