Mistress (title)
You may be looking for the term describing the love interest, .
Mistress was a title given to female leaders or as a term for the lady of the house, especially one who is head of the household.

The William Shakespeare  A Midsummer Night's Dream included the line "My mistress would that he be gone." Beverly Crusher recited this line while trying to fool Mrs. Carmichael into believing they were practicing the play. ()
 
In the context of Klingon society, the mistress of a house, oversaw domestic affairs of the family; including marriages. For example, Lady Sirella, daughter of Linkasa, was Martok's wife and mistress of the House of Martok. As mistress she had the duty of approving all marriages into the family, she came to Deep Space 9 to evaluate Dax's worthiness. Sirella later performed the wedding ceremony. (). The mistress of a house was often referred to as "My Lady" Further, the mistress of a house, could run their house on their own with special permission of the High Council.   

Grilka and Lursa were also called mistress by their subordinates. (; )

It could also be a term of respect for a female in a position of governmental or ranking authority. The Eymorg  was sometimes referred to as Mistress (), as was Lursa. ()

In the matriarchial society of the planet Angel I, the head of government was formed by the Parliament of Angel I consisting of six mistresses and the Elected One. ()

The holographic characters Malicia and Demonica were referred to as "The Twin Mistresses of Evil". ()

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Titles