The Collaborative International Dictionary of English v.0.48:

Bombax \Bom"bax\, n. [LL., cotton. See Bombast, n.] (Bot.)
   A genus of trees, called also the silkcotton tree; also, a
   tree of the genus Bombax.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Bombax
    n 1: trees of chiefly South America [syn: Bombax, genus
         Bombax]