sideroxylon \sid`erox"ylon\, n. nl., fr. gr. ??? iron + ???
   wood. bot.
   a genus of tropical sapotaceous trees noted for their very
   hard wood; ironwood.
   1913 webster

ironwood \i"ronwood`\, n. bot.
   a tree unusually hard, strong, or heavy wood.
   1913 webster

   note: in the united states, the hornbeam and the hop hornbeam
         are so called; also the olneya tesota, a small tree
         of arizona; in the west indies, the erythroxylon
         areolatum, and several other unrelated trees; in
         china, the metrosideros vera; in india, the mesua
         ferrea, and two species of inga; in australia, the
         eucalyptus sideroxylon, and in many countries,
         species of sideroxylon and diospyros, and many
         other trees.
         1913 webster
see also:
olneya tesota erythroxylon areolatum metrosideros vera mesua ferrea inga eucalyptus sideroxylon 
sideroxylon diospyros