1. A condition or place of great disorder or confusion.
2. A disorderly mass; a jumble: The desk was a chaos of papers and unopened letters.
3. often Chaos The disordered state of unformed matter and infinite space supposed in some cosmogonic views to have existed before the ordered universe.
4. Mathematics. A dynamical system that has a sensitive dependence on its initial conditions.
5. Obsolete. An abyss; a chasm.

[Middle English, formless primordial space, from Latin, from Greek khaos.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.