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n. pl. arch·duch·ies
The territory over which an archduke or an archduchess has authority.
[French archiduché, from obsolete French archeduché : arche-, arch- (from Old French; see arch-1) + duché, duchy (from Old French duche; see duchy).]
n, pl -duchies
(Government, Politics & Diplomacy) the territory ruled by an archduke or archduchess
n., pl. -duch•ies.
the domain of an archduke or an archduchess.