from Wiktionary, Creative Commons Attribution/Share-Alike License
- adv. In the manner of a duke; in a way that befits a duke.
from the GNU version of the Collaborative International Dictionary of English
- adv. In the manner of a duke, or in a manner becoming the rank of a duke.
from The Century Dictionary and Cyclopedia
- After the manner of a duke; with a duke or a ducal family: as, ducally connected.
ducal + -ly (Wiktionary)