Wordnet 3.0
VERB (1)
1. 
 strike or tap firmly; 
- Example: "the doctor percussed his chest and back"
The Collaborative International Dictionary of English v.0.48:
Percuss \Per*cuss"\ (p[~e]r*k[u^]s"), v. t. [imp. & p. p.
   Percussed; p. pr. & vb. n. Percussing.] [L. percussus, p.
   p. of percutere; per + quatere to shake, strike. See
   Quash.]
   To strike smartly; to strike upon or against; as, to percuss
   the chest in medical examination.
   [1913 Webster]
         Flame percussed by air giveth a noise.   --Bacon.
   [1913 Webster]
The Collaborative International Dictionary of English v.0.48:
Percuss \Per*cuss"\, v. i. (Med.)
   To strike or tap in an examination by percussion. See
   Percussion, 3. --Quain.
   [1913 Webster]
WordNet (r) 3.0 (2006):
percuss
    v 1: strike or tap firmly; "the doctor percussed his chest and
         back"