The Collaborative International Dictionary of English v.0.48:

Hornbeam \Horn"beam`\, n. [See Beam.] (Bot.)
   A tree of the genus Carpinus (Carpinus Americana), having
   a smooth gray bark and a ridged trunk, the wood being white
   and very hard. It is common along the banks of streams in the
   United States, and is also called ironwood. The English
   hornbeam is Carpinus Betulus. The American is called also
   blue beech and water beech.
   [1913 Webster]

   Hop hornbeam. (Bot.) See under Hop.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ironbark \I"ron*bark`\, Ironbark tree \I"ron*bark` tree`\ (Bot.)
   The Australian Eucalyptus Sideroxylon, used largely by
   carpenters and shipbuilders; -- called also ironwood. Also
   applied to other Australian eucalyptuses with a hard, solid
   bark
   [1913 Webster +PJC]

The Collaborative International Dictionary of English v.0.48:

Ironwood \I"ron*wood`\, 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]

The Collaborative International Dictionary of English v.0.48:

Titi \Ti"ti\, n. [Orig. uncert.]
   1. A tree of the southern United States (Cliftonia
      monophylla) having glossy leaves and racemes of fragrant
      white flowers succeeded by one-seeded drupes; -- called
      also black titi, buckwheat tree, and ironwood.
      [Webster 1913 Suppl.]

   2. Any related tree of the genus Cyrilla, often disting. as
      white titi.
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

ironwood
    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: exceptionally tough or hard wood of any of a number of
       ironwood trees
    3: a small slow-growing deciduous tree of northern Iran having a
       low domed shape [syn: iron tree, iron-tree, ironwood,
       ironwood tree]
    4: medium-sized hop hornbeam of eastern North America [syn:
       Eastern hop hornbeam, ironwood, ironwood tree, Ostrya
       virginiana]

U.S. Gazetteer Places (2000):

Ironwood, MI -- U.S. city in Michigan
   Population (2000):    6293
   Housing Units (2000): 3349
   Land area (2000):     6.553472 sq. miles (16.973415 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    6.553472 sq. miles (16.973415 sq. km)
   FIPS code:            41060
   Located within:       Michigan (MI), FIPS 26
   Location:             46.455931 N, 90.159378 W
   ZIP Codes (1990):     49938
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Ironwood, MI
    Ironwood