A clef is the symbol placed at the beginning of the staff to fix the pitch of the lines and spaces. Without it the five lines would have no absolute meaning. The treble clef centers on G above middle C; the bass clef centers on F below middle C; the alto and tenor clefs are used for mid-range instruments and voices.

Choosing the right clef keeps most notes on the staff rather than on ledger lines. A single piece may change clefs when the music moves into a different register. Keyboard players must read two clefs at once; many other musicians become fluent in only one or two.

The shapes of the clefs evolved from medieval letter forms. Modern notation has standardized them, yet the principle remains the same: the clef tells the reader where the notes sit in the overall pitch spectrum.

• Symbol fixing pitch on the staff
• Treble, bass, alto, and tenor types
• Reduces need for ledger lines
• Essential for reading notation