In baseball, a run is scored when a player advances around first, second and third base and returns safely to home plate, touching the bases in that order, before three outs are recorded and all obligations to reach base safely on batted balls are met or assured. A player may score by hitting a home run or by any combination of plays that puts him safely "on base" as a runner and subsequently brings him home. Once a player has scored a run, they may not attempt to score another run until their next turn to bat. The object of the game is for a team to score more runs than its opponent.

Baseball is a bat-and-ball sport played between two teams of nine players each, taking turns batting and fielding. The game occurs over the course of several plays, with each play generally beginning when a player on the fielding team, called the pitcher, throws a ball that a player on the batting team, called the batter, tries to hit with a bat. The objective of the offensive team is to hit the ball into the field of play, away from the other team's players, allowing its players to run the bases, having them advance counter-clockwise around four bases to score what are called "runs". The objective of the defensive team is to prevent batters from becoming runners, and to prevent runners' advance around the bases. A run is scored when a runner legally advances around the bases in order and touches home plate.