What does the term grand slam mean when playing softball?

In softball, a "grand slam" refers to a home run hit when all three bases are occupied by runners, resulting in the scoring of four runs—one for the batter and one for each of the three runners. It is one of the most exciting plays in the game, as it maximizes the scoring potential in a single at-bat. Hitting a grand slam can significantly shift the momentum of the game and energize the team and fans.