WordNet (r) 3.0 (2006):

ironwood tree
    n 1: 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,
         Mesua ferrea]
    2: a small slow-growing deciduous tree of northern Iran having a
       low domed shape [syn: iron tree, iron-tree, ironwood,
       ironwood tree]
    3: medium-sized hop hornbeam of eastern North America [syn:
       Eastern hop hornbeam, ironwood, ironwood tree, Ostrya
       virginiana]