'Mistress' in the Bible

And he went in to Hagar, and she conceived. And [when] she saw that she had conceived, then her mistress grew small in her eyes.

And he said to Hagar, the servant of Sarai, "{From where} have you come, and where are you going?" And she said, "I am fleeing from the presence of Sarai my mistress."

Then the angel of Yahweh said to her, "Return to your mistress and submit yourself under {her authority}."