archduchess

from WordNet (r) 3.0 (2006)

archduchess
    n 1: a wife or widow of an archduke or a princess of the former
         ruling house of Austria

from The Collaborative International Dictionary of English v.0.48

Archduchess \Arch`duch"ess\, n. [Pref. arch- + duchess.]
   The consort of an archduke; also, a princess of the imperial
   family of Austria. See {Archduke}.
   [1913 Webster]