The general consensus is that there are three sections of an NFL season: the exhibition season, the regular season, and the playoffs. The exhibition season itself is short, and usually only occurs over the course of a month. Once each team has played four exhibition games, the regular NFL season begins.
32 teams currently make up the National Football League, and each of them compete in a 16-game season played over 17 weeks - with the extra week reserved for a bye. This system has been in place since 2002, and allows teams to play opponents in their own division twice, as well as teams from both conferences on a rotating three- to four-year cycle.
For example, the Cleveland Browns are in the AFC North Division, and each season play the Bengals, Ravens, and Steelers twice. In addition, they also play a team from each division in their conference once, and every team from one AFC division once as well. Finally, depending on a rotating calendar, the Browns will play each team from a division in the NFC once, making 16 games for every season.
This schedule means that each team plays every other NFL franchise at least once every four years, and competes in the opponent's stadium at least once every eight years. The NFL differs to a number of different sports and leagues, such as the English Premier League, where clubs play all teams in their specific league twice each season; the sheer number of teams in the NFL makes such a schedule impossible.
Once all teams have completed their 16-game season, the top franchises from each division compete in a 12-team tournament known as the NFL Playoffs. The entire objective of the playoffs is for the two best teams to reach the biggest stage of professional American football: the Superbowl.