High Quality Content by WIKIPEDIA articles! In the sport of baseball, a grand slam is a home run hit with all three bases occupied by baserunners ("bases loaded"), thereby scoring four runs—the most possible in one play. According to The Dickson Baseball Dictionary, the term originated in the card game of contract bridge, in which a grand slam involves taking all the possible tricks. The word slam, by itself, usually is connected with a loud sound, particularly of a door being closed with excess force; thus, slamming the door on one`s opponent(s). The term was extended to various sports, such as golf and tennis, for sweeping a sport`s major tournaments.