The Collaborative International Dictionary of English v.0.48:

Neem tree \Neem" tree`\ [Hind. n[imac]m.] (Bot.)
   An Asiatic name for Melia Azadirachta, and Melia
   Azedarach. See Margosa.
   [1913 Webster]

WordNet (r) 3.0 (2006):

neem tree
    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]