Source : Webster's Revised Unabridged Dictionary (1913)

Succussion \Suc*cus"sion\, n. [L. succussio, from succutere: cf.
   F. succussion. See {Succussation}.]
   The act of shaking; a shake; esp. (Med.), a shaking of the
   body to ascertain if there be a liquid in the thorax.

Source : WordNet®

succussion
     n : shaking a person to determine whether a large amount of
         liquid is present in a body cavity