Abstract: A friction damper that is able to reduce vibrational motions in two dimensions, can be re-used, is easily adjustable and has an extremely smooth transition between sticking and sliding in particular. The friction damper features a stack of at least two friction discs and a prestressing device for this stack. Touching each other at curved contact surfaces, these friction discs are alternately joined with the first and second of two friction damper connections, respectively. The curved contact surfaces can be provided in a simple manner either by an alternate arrangement of lense-shaped and plane friction rings or by alternate arrangement of plane friction rings with convex inserts and plane friction rings.