The Collaborative International Dictionary of English v.0.48:

Cannabin \Can"na*bin\, n. (Chem.)
   A poisonous resin extracted from hemp (Cannabis sativa,
   variety Indica). The euphoric and narcotic effects of
   hasheesh are due to this resin; the active ingredient is
   tetrahydrocannabinol, THC. See Cannabis Indica, below.
   [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

cannabin
    n 1: a resin obtained from the hemp plant; thought to be the
         active narcotic agent in marijuana [syn: cannabin,
         cannabis resin]