Grand Slam (tennis)
The Grand Slam in tennis is the achievement of winning all four major championships in one discipline in the same calendar year, also referred to as the "Calendar-year Grand Slam" or "Calendar Slam". In doubles, a team may accomplish the Grand Slam playing together or a player may achieve it with different partners. Winning all four major championships consecutively but not within the same calendar year is referred to as a "non-calendar-year Grand Slam", while winning the four majors at any point during the course of a career is known as a "Career Grand Slam".
The Grand Slam tournaments, also referred to as majors, are the world's four most important annual professional tennis tournaments. They offer the most ranking points, prize money, public and media attention, the greatest strength and size of field, and the longest matches for men (best of five sets, best of three for the women). The tournaments are overseen by the International Tennis Federation (ITF), rather than the separate men and women's tour organizing bodies, the Association of Tennis Professionals (ATP) and Women's Tennis Association (WTA), but both the ATP and WTA award ranking points based on players' performances in them.
The four Grand Slam tournaments are the Australian Open in January, the French Open from late May to early June, Wimbledon in late June to early July, and the US Open in August–September, with each played over two weeks. The Australian and the United States tournaments are played on hard courts, the French on clay, and Wimbledon on grass. Wimbledon is the oldest tournament, founded in 1877, followed by the US in 1881, the French in 1891, and the Australian in 1905, but it wasn't until 1925 that all four were held as officially sanctioned majors.