umpire
n. countablen. the person who watches a game to make sure players follow the rules. You see them in sports like tennis, baseball, or cricket.
n. an official who enforces the rules of a game and settles disputes between players. Often used in sports where the official remains relatively stationary, such as tennis or cricket.
The umpire called the ball out.
After a long argument on the court, the player finally accepted the umpire's decision and continued the match.
In professional cricket, the field umpires are supported by a third official who reviews video footage to ensure that every decision is as accurate as possible.
From a Middle English rebracketing of a noumpere as an oumpere, from Old French nonper (“odd number, not even (as a tie-breaking arbitrator)”), from non (“not”) + per (“equal”), from Latin par (“equal”). Doublet of nonpareil.
Commonly used in tennis, cricket, and baseball; contrast with 'referee', who typically moves around the field in sports like football or rugby.