Grand Slam is a general sports term applied when achieving something special.
Most common uses:
In tennis, winning the Grand Slam is winning the following four tournaments in the same year: Australian Open, French Open, Wimbledon, US Open. Those tournaments are therefore also known as the Grand Slam tournaments.
... Ottawa
Bibliography
Hogg, P. W., Constitutional law of Canada 4th ed. (Carswell: Scarborough) with Supplement to Constitutional Law of Canada (2002-)
Humphrey, ...