In the sport of baseball, the bases are loaded when there is a runner on each base[1] (1st, 2nd, and 3rd). This presents a great scoring opportunity for the batting team, but it also presents an easy double play opportunity for the defense. Causing the bases to become loaded is called loading the bases. A batter is often intentionally walked when there are runners on 2nd and 3rd base to make it easier for the defense to record more than one out.
A bases-loaded situation is the only time there is a force at home plate.
Since there is no additional room to place the batter, should he be awarded first base from a base on balls or hit by pitch, one run will score due to the third-base player being forced home. In the major leagues, only Abner Dalrymple, Nap Lajoie, Mel Ott, Bill Nicholson, Barry Bonds, and Josh Hamilton hold the distinction of being intentionally walked with the bases loaded.
When a home run is hit with the bases loaded, it is called a grand slam. It scores 4 runs for the batting team, which is the most number of runs that can be scored on a single play.