What is a "mute" used for in music?

A mute is a device used in music to alter the sound produced by an instrument, typically by dampening or softening the volume. This is particularly common in brass instruments like trumpets and trombones, where a mute can change not only the loudness but also the timbre of the sound. When applied, it modifies the vibrations of the instrument, producing a more subdued sound suitable for specific musical contexts or styles.

In this case, the correct answer highlights the primary function of a mute as an attachment that mutes the sound, allowing musicians to create different effects or adapt to various performance settings. Understanding this use of a mute is essential for comprehending the range of expressions available in instrumental music.