In certain sports an official rules on specific aspects of play—safe or out, fair or foul, the height of a net call. That official is an umpire. The title is traditional in baseball, cricket, tennis, and several other disciplines.

Umpires enforce the rules within their area of responsibility and signal decisions clearly so players and spectators understand the outcome. Positioning and concentration are essential. In multi-umpire crews, responsibilities are divided geographically across the field or court.

Like referees, umpires must balance strict rule application with the flow of the contest. Technology now assists in many close calls, yet human umpires still make the majority of real-time judgments. Respect for their role keeps the game orderly.

• Official who rules on plays in specific sports
• Responsible for defined areas or types of decision
• Uses signals to communicate rulings
• Supported increasingly by technological review