League

A league is a group of teams that compete against each other on a regular basis. Leagues can be as small as two teams (see the former East German Oberliga) or as big as a couple dozens (National Hockey League). They can also be amateur, semi-professional or fully professional.

In European systems, it is not rare for leagues to swap one or a couple of teams at the end of each season, as per the promotion and relegation system that is common there. In North America, such a pyramidal system is very rare; leagues are however often tied to each other to various levels, as the higher ranked ones often use the lower ones as development leagues for their younger players.

Leagues can be either major or minor.