What is "studentenverbindung"

Studentenverbindung (often referred to as Verbindung) is the umbrella term for all kinds of fraternity-type associations in German-speaking countries, including Corps, Burschenschaften, Landsmannschaften, Turnerschaften, Sängerschaften, Catholic fraternities, Schwarzburgbund, Wingolf, and Ferialverbindungen. Less than 1% of all current students and living alumni in Germany are active members of a Studentenverbindung.