The Collaborative International Dictionary of English v.0.48:

Mute \Mute\, n.
   1. One who does not speak, whether from physical inability,
      unwillingness, or other cause. Specifically:
      (a) One who, from deafness, either congenital or from
          early life, is unable to use articulate language; a
          deaf-mute.
      (b) A person employed by undertakers at a funeral.
      (c) A person whose part in a play does not require him to
          speak.
      (d) Among the Turks, an officer or attendant who is
          selected for his place because he can not speak.
          [1913 Webster]

   2. (Phon.) A letter which represents no sound; a silent
      letter; also, a close articulation; an element of speech
      formed by a position of the mouth organs which stops the
      passage of the breath; as, p, b, d, k, t.
      [1913 Webster]

   3. (Mus.) A little utensil made of brass, ivory, or other
      material, so formed that it can be fixed in an erect
      position on the bridge of a violin, or similar instrument,
      in order to deaden or soften the tone.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

D \D\ (d[=e])
   1. The fourth letter of the English alphabet, and a vocal
      consonant. The English letter is from Latin, which is from
      Greek, which took it from Ph[oe]nician, the probable
      ultimate origin being Egyptian. It is related most nearly
      to t and th; as, Eng. deep, G. tief; Eng. daughter, G.
      tochter, Gr. qyga`thr, Skr. duhitr. See Guide to
      Pronunciation, [root]178, 179, 229.
      [1913 Webster]

   2. (Mus.) The nominal of the second tone in the model major
      scale (that in C), or of the fourth tone in the relative
      minor scale of C (that in A minor), or of the key tone in
      the relative minor of F.
      [1913 Webster]

   3. As a numeral D stands for 500. in this use it is not the
      initial of any word, or even strictly a letter, but one
      half of the sign ? (or ? ) the original Tuscan numeral for
      1000.
      [1913 Webster]