Source : Webster's Revised Unabridged Dictionary (1913)

Chaos \Cha"os\ (k[=a]"[o^]s), n. [L. chaos chaos (in senses 1 &
   2), Gr. cha`os, fr. cha`inein (root cha) to yawn, to gape, to
   open widely. Cf. {Chasm}.]
   1. An empty, immeasurable space; a yawning chasm. [Archaic]

            Between us and there is fixed a great chaos. --Luke
                                                  xvi. 26
                                                  (Rhemish
                                                  Trans.).

   2. The confused, unorganized condition or mass of matter
      before the creation of distinct and orderly forms.

   3. Any confused or disordered collection or state of things;
      a confused mixture; confusion; disorder.

Source : WordNet®

chaos
     n 1: a state of extreme confusion and disorder [syn: {pandemonium},
           {bedlam}, {topsy-turvydom}, {topsy-turvyness}]
     2: the formless and disordered state of matter before the
        creation of the cosmos
     3: (Greek mythology) the most ancient of gods; the
        personification of the infinity of space preceding
        creation of the universe
     4: (physics) a dynamical system that is extremely sensitive to
        its initial conditions

Source : Free On-Line Dictionary of Computing

chaos
     
        A property of some non-linear dynamic systems which exhibit
        sensitive dependence on initial conditions.  This means that
        there are initial states which evolve within some finite time
        to states whose separation in one or more dimensions of state
        space depends, in an average sense, exponentially on their
        initial separation.  Such systems may still be completely
        {deterministic} in that any future state of the system depends
        only on the initial conditions and the equations describing
        the change of the system with time.  It may, however, require
        arbitrarily high precision to actually calculate a future
        state to within some finite precision.
     
        ["On defining chaos", R. Glynn Holt
         and D. Lynn Holt
        .
       
     {(ftp://mrcnext.cso.uiuc.edu/pub/etext/ippe/preprints/Phil_of_Science/Holt_and_Holt.On_Defining_Chaos)}]
     
        Fixed precision {floating-point} arithmetic, as used by most
        computers, may actually introduce chaotic dependence on
        initial conditions due to the accumulation of rounding errors
        (which constitutes a non-linear system).
     
        (1995-02-07)