the GNU version of the Collaborative International Dictionary of English
n. Lady; a lady; -- a title formerly given to noble ladies who held a barony in their own right.
The Century Dictionary and Cyclopedia
n. In law, a title formerly given to an honorable woman who held a barony in her own right.
Word Usage
"So the presence of the leader's wife or girlfriend wasn't necessarily against Procedures; all that probably changed was the title, if people started calling her queen instead of 'domina'."