The definition of sports law is the law that pertains to sports. There are many laws in sports, many of which overlap. There have been historical cases that have to do with different sports and law areas. The most important of these is the NCAA or National Collegiate Athletic Association. The NCAA is the governing body for Collegiate Sports which means Sports in colleges and universities. In fact, over 50% of the members of this organization are sponsored by state governments.
Another important law and sports has to do with equality among the sexes. Title IX, passed in 1972, makes it illegal for any university that receives Federal funding to discriminate against students because of their gender or their sex. It was this law that allowed women equal opportunities to participate in sports.
For professional athletes, there are other regulating bodies like the National Football League or the National Basketball Association. These organizations determine the rules for things like fairness among different leagues and how individuals who are a part of different leagues are expected to perform and behave. For example, the status of a team and a player can be dictated by whether they use illegal drugs. These organizations have mandatory drug testing, thanks to NCAA v. Tarkanian 109 U.S. 454 (1988).