The term RBI PART is an acronym for RUN Batted In, which is a statistic used in baseball to measure the number of runs a batter scores due to their own action. The three letter solution for this acronym is RUN. This statistic is used to measure how many runs a batter has scored due to their own action, such as a hit, sacrifice fly, or ground out. It is one of the most important statistics in baseball and is used to measure a player's offensive performance.