In 2000, the AL and NL were dissolved as legal entities, and MLB became a single, overall league "de jure", similar to the National Football League (NFL), National Basketball Association (NBA) and National Hockey League (NHL)—albeit with two components called "leagues" instead of "conferences". The same rules and regulations are used in both leagues, with one exception: the AL operates under the designated hitter (DH) rule, while the NL does not. This difference in rules between leagues is unique to MLB; the other sports leagues of the U.S. and Canada have one set of rules for all teams.