The Collaborative International Dictionary of English v.0.48:

Poon \Poon\, n. [Canarese ponne.]
   A name for several East Indian, or their wood, used for the
   masts and spars of vessels, as Calophyllum angustifolium,
   Calophyllum inophullum, and Sterculia f[oe]tida; --
   called also peon.
   [1913 Webster]