The Collaborative International Dictionary of English v.0.48:

azadirachtin \azadirachtin\ n.
   1. a triterpenoid (C35H44O16) isolated from the seeds of
      the neem tree (Azadirachta indica), used as an
      insecticide.
      [WordNet 1.5 +PJC]

WordNet (r) 3.0 (2006):

Azadirachta indica
    n 1: large semi-evergreen tree of the East Indies; trunk exudes
         a tenacious gum; bitter bark used as a tonic; seeds yield
         an aromatic oil; sometimes placed in genus Melia [syn:
         neem, neem tree, nim tree, margosa, arishth,
         Azadirachta indica, Melia Azadirachta]