'Mistress' in the Bible

He went in to [the bed of] Hagar, and she conceived; and when she realized that she had conceived, she looked with contempt on her mistress [regarding Sarai as insignificant because of her infertility].

And He said, “Hagar, Sarai’s maid, where did you come from and where are you going?” And she said, “I am running away from my mistress Sarai.”

The Angel of the Lord said to her, “Go back to your mistress, and submit humbly to her authority.”