A ten-tonne earthquake bomb used by the Royal Air Force in World War II; see Grand Slam (bomb) on Wikipedia.
winning in each of the three Philippine Basketball Association (PBA) tournaments, each called locally a conference, in a season; see Grand Slam (PBA) on Wikipedia.
Victory in every game in the Six Nations competition between England, Wales, Scotland, Ireland, France and Italy
The four (or five) biggest competitions of the year; see Grand Slam (golf) on Wikipedia.
winning in each of the three UEFA cups - UEFA Champions League, UEFA Europa League and Cup Winners' Cup (defunct).
Victory by a Southern Hemisphere national team over all of the Home Nations—England, Wales, Scotland, and Ireland—in a single tour
The four biggest competitions of the year: Wimbledon, the French Open, Australian Open and the US Open
A Soviet-developed tactical ballistic missile.