1. Abbreviation used on the staff to designate common time.
2. The first note (tonic) in the C major scale. In solfeggio it is normally called do, except in France where it is called Ut. The frequencies of the audible pitches of C are notated below.
3. The note Ut of the Guidonian System.
4. The note from which pianos and organs are typically tuned.

See also [Eng.] C; [Fr.] Ut; [Ger.] C; [It.] Do; [Sp.] Do.