Baseball is a popular sport in the United States and many other countries. It has its own set of abbreviations that are used to describe various aspects of the game. The term BASEBALL ABBR. can refer to any of these abbreviations. Two of the most common abbreviations are ERA, which stands for Earned Run Average, and RBI, which stands for Runs Batted In. ERA is a statistic used to measure the number of earned runs a pitcher gives up over a certain period of time, while RBI is a statistic used to measure the number of runs a batter drives in during a game.