The Collaborative International Dictionary of English v.0.48:

Zamang \Za*mang"\, n. (Bot.)
   An immense leguminous tree (Pithecolobium Saman) of
   Venezuela. Its branches form a hemispherical mass, often one
   hundred and eighty feet across. The sweet pulpy pods are used
   commonly for feeding cattle. Also called rain tree. --J.
   Smith (Dict. Econ. Plants).
   [1913 Webster]

WordNet (r) 3.0 (2006):

rain tree
    n 1: large ornamental tropical American tree with bipinnate
         leaves and globose clusters of flowers with crimson stamens
         and seed pods that are eaten by cattle [syn: rain tree,
         saman, monkeypod, monkey pod, zaman, zamang,
         Albizia saman]