'Slave girl' in the Bible

And the daughter of Pharaoh came down to bathe at the river. And her maidens walked along by the riverside. And when she saw the ark among the reeds, she sent her slave-girl to bring it.

And all the first-born in the land of Egypt shall die, from the first-born of Pharaoh that sits upon his throne, even to the first-born of the slave-girl that is behind the mill; also the first-born of beasts.