Tennis is a racket sport that can be played individually against a single opponent (singles) or between two teams of two players each (doubles). Each player uses a tennis racket that is strung with cord to strike a hollow rubber ball covered with felt over or around a net and into the opponent's court. The object of the game is to maneuver the ball in such a way that the opponent is not able to play a valid return. The player who is unable to return the ball will not gain a point, while the opposite player will.
Tennis is an Olympic sport and is played at all levels of society and at all ages. The sport can be played by anyone who can hold a racket, including wheelchair users. The modern game of tennis originated in Birmingham, England, in the late 19th century as lawn tennis. It had close connections both to various field (lawn) games such as croquet and bowls as well as to the older racket sport today called real tennis. During most of the 19th century, in fact, the term tennis referred to real tennis, not lawn tennis: for example, in Disraeli's novel Sybil (1845), Lord Eugene De Vere announces that he will "go down to Hampton Court and play tennis. "The rules of modern tennis have changed little since the 1890s. Two exceptions are that from 1908 to 1961 the server had to keep one foot on the ground at all times, and the adoption of the tiebreak in the 1970s. A recent addition to professional tennis has been the adoption of electronic review technology coupled with a point-challenge system, which allows a player to contest the line call of a point, a system known as Hawk-Eye.
Tennis is played by millions of recreational players and is also a popular worldwide spectator sport. The four Grand Slam tournaments (also referred to as the Majors) are especially popular: the Australian Open played on hard courts, the French Open played on red clay courts, Wimbledon played on grass courts, and the US Open also played on hard courts.
The Grand Slam tournaments, also called majors, are the four most important annual tennis events. They offer the most ranking points, prize money, public and media attention, the greatest strength and size of field, and greater number of "best of" sets for men. The Grand Slam itinerary consists of the Australian Open in mid January, the French Open in May and June, Wimbledon in July, and the US Open in August and September. Each tournament is played over a period of two weeks. The Australian and United States tournaments are played on hard courts, the French on clay, and Wimbledon on grass. Wimbledon is the oldest, founded in 1877, followed by the US in 1881, the French in 1891, and the Australian in 1905. However, of these four, only Wimbledon was a major before 1924–25, when all four became designated Grand Slam tournaments. Skipping majors—especially the Australian Open because of the remoteness, the inconvenient dates (around Christmas and New Year's Day) and the low prize money—was not unusual before 1982.
Grand Slam tournaments are not operated by the Association of Tennis Professionals (ATP) or the Women's Tennis Association (WTA), which were formally founded in 1972 and 1973 respectively, though the ATP and WTA do award ranking points based on a player's performance at a major.The term Grand Slam, without qualification, and also originally, refers to the achievement of winning all four major championships within a single calendar year within one of the five events: men's and women's singles; men's, women's, and mixed doubles. In doubles, one team may accomplish a Grand Slam playing together or one player may achieve it with different partners.Winning the four majors in consecutive tournaments but not in the same year is known as a Non-Calendar Year Grand Slam, while winning all four majors at any point during the course of a career is known as a Career Grand Slam. Winning the gold medal at the Summer Olympic Games in addition to the four majors in one calendar year is known as a "Golden Grand Slam" or more commonly the "Golden Slam". Also, winning the Year-End Championship (known as ATP Finals for men's singles and doubles disciplines, and WTA Finals for both women's disciplines) in the same period is known as a "Super Slam". Together, all four majors in all three disciplines (singles, doubles, and mixed doubles) are called a "boxed set" of Grand Slam titles. No male or female player has won all twelve events in one calendar year, although a "career boxed set" has been achieved by three female players.