The term DIAMOND OFFICIAL is used to refer to two different roles in the sport of baseball. The first role is an UMP, which stands for UMPIRE. An UMPIRE is responsible for making decisions on the field during a game, such as calling balls and strikes, determining whether a runner is safe or out, and ruling on other plays. The second role is an UMPIRE, which stands for UMPIRE-in-chief. This person is responsible for overseeing all umpires and making sure that they are following the rules of the game. They also have the authority to eject players or coaches from the game if necessary.