In physics this relates to decreasing the amplitude of a wave, whether represented electrically or mechanically. In acoustic instruments we refer to the mechanical context, where we may dampen or reduce the vibration of strings on a piano, guitar, bass, etc. Applying muffling to drums and other instruments would also qualify. In acoustics this could refer to reducing sympathetic vibrations or the acoustic reflectivity of something. For example, applying acoustic absorbers to a wall surface or the inside of a speaker cabinet effectively dampens or reduces reflections.