Source : Webster's Revised Unabridged Dictionary (1913)

Contrecoup \Con`tre*coup"\, n. [F., fr. contre (L. contra) +
   coup a blow.] (med.)
   A concussion or shock produced by a blow or other injury, in
   a part or region opposite to that at which the blow is
   received, often causing rupture or disorganisation of the
   parts affected.