Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
An umpire or arbiter or judge (Job 9:33). This word is formed from the Latin diem dicere, i.e., to fix a day for hearing a cause. Such an one is empowered by mutual consent to decide the cause, and to "lay his hand", i.e., to impose his authority, on both, and enforce his sentence.