A tuned mass damper is a device used to reduce vibrations in structures, such as buildings and bridges. It consists of a mass that is mounted on springs and dampers, which are tuned to resonate at the same frequency as the unwanted vibrations. When the structure moves, the damper moves in the opposite direction, helping to absorb and dissipate energy. These devices are particularly useful in tall buildings, where wind or seismic activity can cause swaying. By effectively counteracting these forces, tuned mass dampers enhance the comfort and safety of occupants, making structures more resilient against dynamic loads.