clef
A symbol at the beginning of a staff indicating the pitch of the notes.
In Depth
A clef fixes the pitches on a staff by assigning a specific note to a specific line. The treble clef (G clef) places G4 on the second line, the bass clef (F clef) places F3 on the fourth line, and the various C clefs place middle C on different lines depending on the instrument or voice.
The alto clef, a C clef centered on the third line, is used primarily by the viola. The tenor clef places middle C on the fourth line and is used for upper-range passages on cello, bassoon, and trombone. Reading multiple clefs is an essential skill for conductors and composers.
The treble clef is actually a stylised letter G — the spiral at its centre wraps around the second staff line, which is the note G. The bass clef is a stylised F.