Related Clues:

• Flag bearer
• Official in a striped shirt
• Worker among players
• O.E.D., e.g.
• Ruling official
• KO caller
• Ump's football counterpart
• Fight stopper, maybe
• He calls the shots
• Dict., for one
• Sports "zebra"
• "Offside" official
• One may determine if a line has been crossed
• Maker of calls
• Official who ensures fair play