ducally
du·cal
(do͞o′kəl, dyo͞o′-)adj.
Of or relating to a duke or duchy: a ducal estate.
[Middle English, from Old French, from Late Latin ducālis, from Latin dux, duc-, leader; see duke.]
du′cal·ly adv.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.