um·pire n: a person having authority to decide finally a controversy or question between parties: as
a: one appointed to decide between disagreeing arbitrators
b: an impartial third party chosen to arbitrate disputes arising under the terms of a labor agreement
c: one appointed to mediate between the appraisers of an insured and insurer in order to determine the amount of a loss
Merriam-Webster’s Dictionary of Law. Merriam-Webster. 1996.