'Freewoman' in the Bible

For it is written, that Abraham had two sons, the one by a bondmaid, the other by a freewoman.

But he who was of the bondwoman was born after the flesh; but he of the freewoman was by promise.

Nevertheless what saith the scripture? Cast out the bondwoman and her son: for the son of the bondwoman shall not be heir with the son of the freewoman.