Professional gridiron football in the context of "NFL"

Gridiron football (/ˈɡrɪdaɪ.ərn/ GRID-eye-ərn), also known as North American football, or in North America as simply football, is a family of team sports derived from rugby football (and football, by extension) primarily played in the United States and Canada.

American football, which uses 11 players, is the form played in the United States and the best known form of gridiron football worldwide, while Canadian football, which uses 12 players, predominates in Canada. Other derivative varieties include arena football, flag football and amateur games such as touch and street football. Football is played at professional, collegiate, high school, semi-professional, and amateur levels.

The National Football League (NFL) is a professional American football league in the United States. Composed of 32 teams, it is divided equally between the American Football Conference (AFC) and the National Football Conference (NFC). The NFL is one of the major professional sports leagues in the United States and Canada and the highest professional level of American football in the world. Each NFL season begins annually with a three-week preseason in August, followed by the 18-week regular season, which runs from early September to early January, with each team playing 17 games and having one bye week. Following the conclusion of the regular season, seven teams from each conference, including the four division winners and three wild card teams, advance to the playoffs, a single-elimination tournament, which culminates in the Super Bowl, played in early February between the winners of the AFC and NFC championship games. The NFL is headquartered in Midtown Manhattan.

The NFL was formed in 1920 as the American Professional Football Association (APFA) before renaming itself the National Football League for the 1922 season. After initially determining champions through end-of-season standings, a playoff system was implemented in 1933 that culminated with the NFL Championship Game until 1966. Following an agreement to merge the NFL with the rival American Football League (AFL), the Super Bowl was first held in 1967 to determine a champion between the best teams from the two leagues and has remained as the final game of each NFL season since the merger was completed in 1970. The NFL is the wealthiest professional sports league in the world by revenue, and the sports league with the most valuable teams. The NFL also has the highest average attendance (67,591) of any professional sports league in the world and is the most popular sports league in the United States. The Super Bowl is also among the most-watched sporting events in the world, with the individual games accounting for many of the most watched television programs in American history and occupying the top five of Nielsen's all-time most-watched U.S. television broadcasts by 2015.

The United Football League (UFL) is a professional American football spring league in the United States. The league was created following the merger of the latest iterations of the XFL and United States Football League (USFL); it started play in March 2024. It comprises eight teams, five of which were members of the XFL or USFL prior to the UFL's creation, and all concentrated in the Midwest and Southern United States.

The Canadian Football League (CFL; French: Ligue canadienne de football [liɡ kanadjɛn də futbol], LCF) is a professional Canadian football league in Canada. It comprises nine teams divided into two divisions, with four teams in the East Division and five in the West Division. The CFL is the highest professional level of Canadian football in the world. The league is headquartered in Toronto.

The CFL was officially established on January 19, 1958, upon the merger between the Interprovincial Rugby Football Union or "Big Four" (founded in 1907) and the Western Interprovincial Football Union (WIFU) (founded in March 1936). The Big Four was renamed the Eastern Football Conference in 1960, while the WIFU was renamed the Western Football Conference in 1961.