1. A deaf person who is unable to speak; SYN. deaf-mute, deaf-and-dumb person.
2. A device used to soften the tone of a musical instrument.

ETYM Latin mutus; cf. Greek myein to shut, Skr. muta bound, muka dumb: cf. Old Eng. muet, from French muet, a dim. of Old Fren. mu, Latin mutus.
1. Expressed without speech; especially because words would be inappropriate or inadequate; SYN. tongueless, unspoken, wordless.
2. Lacking power of speech; SYN. tongueless.

In music, any device used to dampen the vibration of an instrument and so affect the tone. Orchestral strings apply a form of clamp to the bridge—the change is used to dramatic effect by Bartók in the opening bars of Music for Strings, Percussion, and Celesta 1936. Brass instruments use the hand or a plug of metal or cardboard inserted in the bell.
Although the word implies a reduction of volume, a variety of mutes used in big band jazz are used principally to vary the quality of tone, as in Stravinsky’s Ebony Concerto 1945.

1. To muffle, reduce, or eliminate the sound of
2. To tone down; soften, subdue
3. Of a bird; to evacuate the cloaca