Source : Webster's Revised Unabridged Dictionary (1913)

Centaury \Cen"tau*ry\, n. [L. centaureum and centauria, Gr. ?,
   ?, and ?, fr. the Centaur Chiron.] (Bot.)
   A gentianaceous plant not fully identified. The name is
   usually given to the {Eryther[ae]a Centaurium} and the
   {Chlora perfoliata} of Europe, but is also extended to the
   whole genus {Sabbatia}, and even to the unrelated
   {Centaurea}.

Source : WordNet®

centaury
     n 1: any of various plants of the genus Centaurium
     2: any plant of the genus Centaurea