The Collaborative International Dictionary of English v.0.48:

Osage orange \O"sage or"ange\ (Bot.)
   An ornamental tree of the genus Maclura (Maclura
   aurantiaca), closely allied to the mulberry (Morus); also,
   its fruit. The tree was first found in the country of the
   Osage Indians, and bears a hard and inedible fruit of an
   orangelike appearance. See Bois d'arc.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Bois d'arc \Bois" d'arc"\ [F., bow wood. So called because used
   for bows by the Western Indians.] (Bot.)
   The Osage orange (Maclura aurantiaca).
   [1913 Webster]

         The bois d'arc seems to be the characteristic growth of
         the black prairies.                      --U. S. Census
                                                  (1880).
   [1913 Webster]