Arbitrator
'ARBITRATOR, noun A person chosen by a party, or by the parties who have a controversy, to determine their differences. The act of the parties in giving power to the arbitrators is called the submission, and this may be verbal or written. The person chosen as umpire, by two arbitrators, when the parties do not agree, is also called an arbitrator
2. An arbiter, governor, or president.
3. In a more extensive sense, an arbiter; one who has the power of deciding or prescribing without control.