In some sports, a referee is a person who has authority to make decisions about play. Also, in normal life, a referee is someone who provides a reference for another person: for example, one's former employers might provide one with a reference when applying for a job.
The term referee originated in football (soccer). Originally the team captains would consult with each other in order to resolve any dispute on the pitch. Eventually this role was delegated to an umpire. Each team would bring their own partisan umpire allowing the team captains to concentrate on the game. Later, the referee, a third "neutral" official was added. The referee would be "referred to" if the umpires could not resolve a dispute. The referee did not take his place on the pitch until 1891, when the umpires became linesmen (now officially called assistant referees). Today, in many amateur football matches, each side will still supply their own partisan assistant referees (still often called club linesmen) to assist the neutral referee appointed by the governing football association.
An association football (soccer) match is presided over by a referee, whom the Laws of the Game give "full authority to enforce the Laws of the Game in connection with the match to which he has been appointed" (Law 5). The referee is assisted by two assistant referees and possibly by a fourth official.
In cricket, the match referee is an off-field official who only makes judgments concerning the reputable conduct of the game and hands out penalties for breaches of the ICC Cricket Code of Conduct. On-field decisions relevant to the play and outcome of the game itself are handled solely by on-field umpires.