English Reference
noun

chaos

n.
US /ˈkeɪɑs/ UK /kˈeɪɒs/ chaos UK spelling chaoses

  1. 01 B2 Upper Intermediate

    a situation where everything is happening at once and there is no order.

    a state of utter confusion or disorder; a total lack of organization or predictability.

    Simple

    The station was in total chaos after all the trains were cancelled.

    In context

    The sudden withdrawal of funding threw the entire research department into a state of chaos, leaving dozens of projects unfinished.

  2. 02 C1 Advanced Technical Science

    a type of math or science where very small changes can lead to huge, unpredictable results.

    the property of a complex system where small variations in initial conditions result in massive differences in later states.

    Simple

    Weather is a great example of chaos because a tiny change in wind can change a whole storm.

    In context

    In mathematics, chaos describes systems that appear random but are actually governed by sensitive, non-linear laws.

    Usage

    Often used in the phrase 'chaos theory'.

  3. 03 C2 Proficiency LiteraryAcademic Religion

    the empty space or confusion that existed before the world was created in ancient stories.

    the primordial void or state of matter preceding the creation of the universe in various cosmogonies.

    Simple

    In ancient Greek myths, the universe began as a dark chaos.

    In context

    The poet describes the transition from primordial chaos to the structured harmony of the heavens.

Inside we're hurting but it doesn't mean we all have to shout and scream and come out and create some chaos.

BBC News· 22 Aug 2026

If continuity is the key word in Coventry’s fight for survival then chaos seems to be Hull’s.

The Guardian· 14 Aug 2026

Learned borrowing from Ancient Greek χάος (kháos, “vast chasm, void”). Doublet of gas, which was borrowed through Dutch. In Early Modern English, used in the sense of the original Greek word. In the meaning "primordial matter" from the 16th century. Figurative usage in the sense "confusion, disorder" from the 17th century. The technical sense in mathematics and science dates from the 1960s.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Level C1 · Advanced
Frequency Common
Updated