Source : Webster's Revised Unabridged Dictionary (1913)

Papaverine \Pa*pav"er*ine\, n. (Chem.)
   An alkaloid found in opium. It has a weaker therapeutic
   action than morphine.

Source : WordNet®

papaverine
     n : an alkaloid medicine (trade name Kavrin) obtained from
         opium; used to relax smooth muscles; it is nonaddictive
         [syn: {Kavrin}]