National Football League
The NFL is one of the four major North American professional sports leagues. The National Football League is a professional American football league made up of 32 teams equally divided between the National Football Conference (NFC) and the American Football Conference (AFC).
The NFL consists of 32 clubs divided into two conferences of 16 teams in each. Each conference is divided into four divisions of four clubs in each. During the regular season, each team is allowed a maximum of 55 players on its roster, only 48 of these may be active on game days. Each team can also have a 12 player practice squad separate from its main roster.
The NFL's 17-week regular season runs from early September to late December, with each team playing 16 games and having one farewell week. After the end of the regular season, seven teams from each conference (four division winners and three wild card teams) advance to the playoffs, a single elimination knockout tournament culminating in the Super Bowl, usually held on the first Sunday in February and played between NFC champions and AFC.
Most NFL games are played on Sundays, with a Monday night game typically held at least once a week and Thursday night games occurring on most weeks as well.
NFL regular season matches are determined according to a schedule formula. In a division, all four teams play fourteen of their sixteen games against common opponents - two games (home and away) are played against three other teams in the division, and one game is played against all members of the division from NFC and a unit from AFC according to the rotation cycle (three years for a conference in which the team participates, and four years for a conference in which they are not participating). The other two games are intra-conference games defined by the previous year's standings - for example, if a team finishes first in its division, it will play against the other two first-place teams in its conference, and the team that finishes last will play two other teams who took the last places in the conference. In total, each team plays sixteen games and has one free week during which they do not play any games.