A ref, short for referee, is a person responsible for enforcing the rules and ensuring fair play during a game or sporting event. They make decisions, give penalties, and resolve disputes between players or teams. Generally, they act as neutral figures and are often the ones who call "fouls" or violations.
Note: The provided meaning of the answer is for the latest New York Times crossword puzzle clue: Traveling caller, perhaps. Explanations are generated by AI and may be inaccurate.