Grand Slam

(Britain, soccer) winning in each of the three UEFA cups - UEFA Champions League, UEFA Europa League and Cup Winners' Cup (defunct).

(tennis) The four biggest competitions of the year: Wimbledon, the French Open, Australian Open and the US Open

(rugby) Victory in every game in the Six Nations competition between England, Wales, Scotland, Ireland, France and Italy

(rugby) Victory by a Southern Hemisphere national team over all of the Home Nations—England, Wales, Scotland, and Ireland—in a single tour

(golf) The four (or five) biggest competitions of the year; see Grand Slam (golf) on Wikipedia.

(military) A ten-tonne earthquake bomb used by the Royal Air Force in World War II; see Grand Slam (bomb) on Wikipedia.

(Philippines, basketball) 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.