\Clef\ (kl[e^]f; 277), n. [F. clef key, a key in music, fr.
L. clavis key. See {Clavicle}.] (Mus.)
A character used in musical notation to determine the
position and pitch of the scale as represented on the staff.
Note: The clefs are three in number, called the C, F, and G
      clefs, and are probably corruptions or modifications of
      these letters. They indicate that the letters of
      absolute pitch belonging to the lines upon which they
      are placed, are respectively C, F, and G. The F or bass
      clef, and the G or treble clef, are fixed in their
      positions upon the staff. The C clef may have three
      positions. It may be placed upon the first or lower
      line of the staff, in which case it is called soprano
      clef, upon the third line, in which case it called alto
      clef, or upon the fourth line, in which case tenor
      clef. It rarely or never is placed upon the second
      line, except in ancient music. See other forms of C
      clef under C, 2.
{Alto clef}, {Bass clef}. See under {Alto}, {Bass}.