Nahor, Abraham's brother, had a son through his concubine Reumah.
Genesis 22:23These eight were born to Milcah, the wife of Nahor, Abraham’s brother. And Bethuel became the father of Rebekah.Genesis 22:24His concubine, whose name was Reumah, also bore children: Tebah, Gaham, Dahash and Maacah.
[See Abraham's Family Tree]