The term 'Diamond Arbiter' is a combination of two words: UMPIRE and UMP. An UMPIRE is an official in a variety of sports who is responsible for enforcing the rules of the game and making decisions on the field. An UMP is a shortened version of the word UMPIRE, and is commonly used in baseball. The Diamond Arbiter is a person who is responsible for making sure that the rules of the game are followed and that all players are playing fairly.