USSL meaning in Sports ?

The United States soccer league system is a series of professional and amateur soccer leagues based, in whole or in part, in the United States. Sometimes called the American soccer pyramid, teams and leagues are not linked by the system of promotion and relegation typical in soccer elsewhere. Instead, the United States Soccer Federation (USSF) defines professional leagues in three levels, called divisions, with all other leagues sanctioned by the USSF not having an official designated level or division.

For practical and historical reasons, some teams from Bermuda, Canada, and Puerto Rico (considered a separate country by FIFA) can also compete in these leagues. However, these teams are not eligible for the U.S. Open Cup and cannot represent the United States in the CONCACAF Champions League because they are not affiliated with U.S. Soccer.