1911 Encyclopædia Britannica/Umpire

UMPIRE, the term used, like “referee,” for a person appointed by consent to settle disputes arising between opposing parties, and particularly one chosen to see that the rules of a game are obeyed. The word itself stands for the Middle English nompere or noumpere, “a numpere” becoming “an umpire.” The earlier form represents the Old French nompere, nonpair, i.e. not equal, odd. The Latin impar, unequal, was similarly used in the sense of “arbitrator.”