'Mistress' in the Bible

And he went in to Hagar, and she conceived. And when she saw that she had conceived, her mistress was lightly esteemed in her eyes.

And he said, Hagar, Sarai's maidservant, whence comest thou? and whither art thou going? And she said, I am fleeing from the face of my mistress Sarai.

And the Angel of Jehovah said to her, Return to thy mistress, and submit thyself under her hands.