Source : Webster's Revised Unabridged Dictionary (1913)

Ironwood \I"ron*wood`\, n. (Bot.)
   A tree unusually hard, strong, or heavy wood.

   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.

Source : WordNet®

Mesua ferrea
     n : handsome East Indian evergreen tree often planted as an
         ornamental for its fragrant white flowers that yield a
         perfume; source of very heavy hardwood used for railroad
         ties [syn: {rose chestnut}, {ironwood}, {ironwood tree}]