Adjective
Of or pertaining to a grand duke.
Source: Webster's dictionarygrand ducal
Baden's grand-ducal family faced extinction, so Leopold was enfranchised by international treaty and married to a princess, ascending the throne in 1830. Source: Internet
There is a Kurhaus, built in 1853, and a park of 15 acres (61,000 m²) containing a historic arboretum (the Staatliche Baderverwaltung Badenweiler ), as well as a grand-ducal castle, refitted in 1887–88. Source: Internet