Wiktionary
n. A form of rugby union, played on a full-size pitch but with only seven players per side.
Wikipedia
Rugby sevens is a variant of rugby union in which teams are made up of seven players playing seven-minute halves, instead of the usual 15 players playing 40-minute halves. Rugby sevens is administered by World Rugby, the body responsible for Rugby Union worldwide.The game is popular at all levels, with amateur and club tournaments generally held in the summer months. Sevens is one of the most well distributed forms of rugby, and is popular in parts of Africa, Asia, Europe, and the Americas, and especially in the South Pacific. Rugby sevens is commonly referred to by rugby union media and fans as simply "sevens".
Rugby sevens originated in Melrose, Scotland in the 1880s; the Melrose Sevens tournament is still played annually. The popularity of rugby sevens increased further with the development of the Hong Kong Sevens in the 1970s, the World Rugby Sevens Series in 1999, and more recently with the 2009 vote by the International Olympic Committee to bring rugby back to the Olympics beginning in 2016.
The main competition for rugby sevens is the World Rugby Sevens Series, a series of seven to twelve tournaments played each year from approximately November to May. Rugby sevens is also played at some quadrennial events. The main quadrennial events are the Rugby World Cup Sevens and the Summer Olympics. Rugby sevens is now recognised as an Olympic sport and made its debut in the 2016 Summer Olympics. This follows a vote by the International Olympic Committee in 2009 to include the sport. Rugby sevens is also played at regional events, such as the Commonwealth Games and the Pan American Games.