The 05 in the name of German football club FSV Mainz 05 refers to the year 1905 when its original predecessor club was founded.
Going by the full name 1. Fußball- und Sportverein Mainz 05, meaning 1st Mainz Football and Sports Club 05, the club has its foundations in the formation of 1. Mainzer Fußballclub Hassia 1905 in March 1905. Following subsequent mergers with other clubs, it became 1. Mainzer Fußball- und Sportverein 05.
In addition to its football team, the present-day FSV Mainz 05 club also has table tennis and women’s handball teams.
Mainz 05 is informally nicknamed Die Nullfünfer, which translates as “the zero fives”.