Source : Webster's Revised Unabridged Dictionary (1913)

Whiplash \Whip"lash`\, n.
   The lash of a whip, -- usually made of thongs of leather, or
   of cords, braided or twisted.

Source : WordNet®

whiplash
     n 1: an injury to the neck (the cervical vertebrae) resulting
          from rapid acceleration or deceleration (as in an
          automobile accident) [syn: {whiplash injury}]
     2: a quick blow with a whip [syn: {whip}, {lash}]