Rosenmontag (English: Rose Monday) is the highlight of the German "Karneval" (carnival), and is on the Shrove Monday before Ash Wednesday, the beginning of Lent. "Mardi Gras," though celebrated on Tuesday, is a similar event. Rosenmontag is celebrated in German-speaking countries, including Germany, Austria, Switzerland and Belgium (Eupen), but most heavily in the "Karnevalshochburgen" (carnival strongholds), which include the Rhineland, especially in Cologne, Bonn, Düsseldorf, Aachen and Mainz. In contrast to Germany, in Austria, the highlight of the carneval is not Rosenmontag, but Faschingsdienstag (Shrove Tuesday).
The name for the carnival comes from the German dialect word roose meaning 'frolic' and Montag meaning Monday.