Source : Webster's Revised Unabridged Dictionary (1913)

Cocaine \Co"ca*ine\, n. (Chem.)
   A powerful alkaloid, {C17H21NO4}, obtained from the leaves of
   coca. It is a bitter, white, crystalline substance, and is
   remarkable for producing local insensibility to pain.

Source : WordNet®

cocaine
     n : a narcotic (alkaloid) extracted from coca leaves; used as a
         surface anesthetic or taken for pleasure; can become
         powerfully addictive [syn: {cocain}]