The Collaborative International Dictionary of English v.0.48:

Zedoary \Zed"o*a*ry\, n. [F. z['e]doaire, LL. zedoaria; cf. It.
   zedoaria, zettovario, Pg. zedoaria, Sp. zedoaria, cedoaria;
   all fr. Ar. & Per. zedw?r.] (Med.)
   A medicinal substance obtained in the East Indies, having a
   fragrant smell, and a warm, bitter, aromatic taste. It is
   used in medicine as a stimulant.
   [1913 Webster]

   Note: It is the rhizome of different species of Curcuma,
         esp. Curcuma zedoaria, and comes in short, firm
         pieces, externally of a wrinkled gray, ash-colored
         appearance, but within of a brownish red color. There
         are two kinds, round zedoary, and long zedoary.
         [1913 Webster]