In baseball, the umpire is the person charged with officiating the game, including beginning and ending the game, enforcing the rules of the game and the grounds, making judgment calls on plays, and handling the disciplinary actions. The term is often shortened to the colloquial form ump. They are also sometimes addressed as blue at lower levels due to the common color of the uniform worn by umpires. In professional baseball, the term "blue" is seldom used by players or managers, who instead call the umpire by his actual name in order to show respect (and to reflect the fact that MLB umpires do not always wear blue). Although games were often officiated by a sole umpire in the formative years of the sport, since the turn of the 20th century officiating has been commonly divided among several umpires, who form the umpiring crew.
Other articles related to "umpire":
... to the Middle English Dictionary entry for noumpere, the predecessor of umpire came from the Old French nonper (from non, "not" + per, "equal"), meaning "one who is ... Thus today we say "an umpire instead of "a numpire." ...