The Grand Slams are made up of the four major tennis tournaments: The Australian Open, The French Open, The Championships at Wimbledon and The US Open.
The term 'Grand Slam' originated from Don Budge's achievement of winning the French Open, Wimbledon, the US Open and the Australian Open in 1938. The distinguished American writer Allison Danzig suggested that like a successful bridge player, Budge had scored a 'Grand Slam' of victories in the four major tennis events in one calendar year.
The phrase gained use in common parlance and now is used to refer to the four most prestigious tennis tournaments in the world. In 1989, the Grand Slams joined forces for the first time to form the Grand Slam Committee which, among other responsibilities, administers the Grand Slam rules.