ED (עֵ֥ד, witness). RSV WITNESS. An altar built by Reubenites, Gadites, and the half-tribe of Manasseh who settled E of the Jordan, as a witness of their loyalty to the God of Israel and to the tribes W of the Jordan. Not in MT or LXX; inserted in KJV, ASV (Josh 22:34).

International Standard Bible Encyclopedia (1915)

(’edh, "witness"):