Haso is the grandson of Terah and the son of Nahor. He is one of the eight sons born to Milcah, the daughter of Haran, and Nahor.
Genesis 22:20Now after these things it was told to Abraham, “Behold, Milcah also has borne children to your brother Nahor:Genesis 22:21Uz his firstborn, Buz his brother, Kemuel the father of Aram,Genesis 22:22Chesed, Haso, Pildash, Idlaph, and Bethuel.”Genesis 22:23Bethuel became the father of Rebekah. These eight Milcah bore to Abraham’s brother Nahor.Genesis 22:24His concubine, whose name was Reumah, also bore children: Tebah, Gaham, Tahash, and Maacah.
[See Abraham's family tree]