Muting is to greatly decrease the volume level. Many receivers and pre-amplifiers have a muting control which allows the volume level to be cut way down without changing the master volume control.
A mute is a device designed to alter an instrument's timbre and that also acts as a silencer, partial or complete. (1) In bowed instruments a small clamp is placed on the bride, producing a silvery tone. (2) In brass instruments a pear-shaped stopper is pushed into the bell (s similar contrivance is occasionally used with woodwind instruments. (3) With the kettledrums muting was formerly effected by placing a cloth over the parchment but it is usual now to employ sponge-headed drumsticks instead.