In sport, the term "regular season" or "home-and-away season" refers to the sport's
league competition. The regular season is usually similar to a
group tournament format: teams are divided into groups, conferences and/or divisions, and each club plays a set number of games against a set number of opponents. In most countries the league is played in a double round-robin format, where every team plays every other team twice, once at their home venue, and once away at the opposition's venue as visitors. The results over all games are accumulated and when every team has completed its full schedule of games, a winner is declared. In North America, the scheduling is different. Rather than every team playing all others twice, teams usually play more games against local rivals than teams in other parts of the country. For example, the
NBA's
Los Angeles Lakers will play the
Los Angeles Clippers (a team within their division, a subdivision of the conference) four times in a regular season, while both will only play the
Toronto Raptors, who are in the opposite
Eastern Conference, twice. Part of this is due to the vast geographic distances between some teams in North America—measured in a straight line, Los Angeles is 3,494 kilometres from Toronto, for instance—and a desire to limit travel expenses. In the scheduling system used in the
NFL, it is possible for two teams to only meet every four years, and to only have 2 common opponents in a season.
Major League Baseball has the most uneven schedules of all the four major North American sports. In MLB, the conferences are called leagues instead, but have exactly the same effect as
conferences (as with all
North American major leagues, leagues, conferences, and division are not based on skill, but instead geography, history, and rivalries). Prior to scheduling changes in 2023, teams played 19 games against each of the teams in their own division each year but only played 20 games total against all of the teams in the other league. Because each of the inter-league match-ups was part of a 3-game series or a 2-game series, teams played no games at all against most teams from the other league. They played 6 of the 15 teams in the other league, a historically high number (until 1997,
interleague play was limited to exhibition matches and the postseason
World Series, and thus MLB teams did not play the other league's teams at all). In 2023, teams played all interleague teams in a single season for the first time; teams now play a 3-game series against all teams, except their designated interleague rival with 4 games, totalling to 46 games (later increased to 48 games and a 6-game series with their interleague rival for the forthcoming 2025 season). In Australia, the two largest football leagues, the
AFL (
Australian rules football) and
NRL (
rugby league), both grew out of competitions held within a single city (respectively Melbourne and Sydney) and only began expanding to the rest of the country when inexpensive air travel made a national league possible. These leagues use a single
table instead of being split into divisions. The term "home and away season" is sometimes used instead of regular season. Many football leagues in Latin America have a very different system. Because most Latin American countries never had a football cup competition, they instead split their season into two parts, typically known as the
Apertura and Clausura (
Spanish for "opening" and "closing"). Most countries that use this system, Argentina being one notable example, crown separate league champions for each part of the season, using only league play. A few others, such as Uruguay, crown one champion at the end of a playoff involving top teams from each half of the season. Mexico operates its Apertura and Clausura as separate competitions that both end in playoffs. Brazil has a different system, the season starts with the state championships in January (every Brazilian state has its own championship), these state championships ends in April. The
Campeonato Brasileiro Série A itself starts in May and ends in early December, and is played in a double round-robin format in the same way as the European championships. A system similar to the Apertura and Clausura developed independently in
Philippine professional basketball, with formerly two, now three tournaments (called "conferences") in one season, with each conference divided into an "elimination round" (the single round-robin group stage) and the playoffs in the North American sense. Winning the playoffs is the ultimate goal of every team for every conference; while there is no season championship,
winning all conferences within a single season is rare and has only happened five times since 1975, with the two most recent examples occurring in
1996 and
2013–14. The qualifying round and playoffs setup has permeated down to the local level and in most team sports, although seasons are not divided into conferences. ==Postseason==