mute

A mute is a device attached to a musical instrument which changes the instrument's tone quality (timbre) or lowers its volume. Mutes are commonly used on string and brass instruments, especially the trumpet and trombone, and are occasionally used on woodwinds. Their effect is mostly intended for artistic use, but they can also allow players to practice discreetly. Muting can also be done by hand, as in the case of palm muting a guitar or grasping a triangle to dampen its sound.