("the thumb".) A son of Reuben (not mentioned in Exodus 6:14; Numbers 26:5; 1 Chronicles 5:3), after whom a stone was named. Probably commemorating some achievement of his in the conquest of Israel (Joshua 15:6; Joshua 18:17). It was a boundary mark between Judah and Benjamin, the exact point where the mountains W. of the Dead Sea change their direction to the eye. Now called "the stone of the finger," Hadjar el Asbah. Ganneau observes that a rock on an isolated peak on the hill side resembles a fist closed with the thumb raised; the name of this peak probably was transferred to the fallen block close by, namely, Hadjar el Asbah.