C (musical note)

C or Do is the first note of the C major scale, the third note of the A minor scale (the relative minor of C major), and the fourth note (G, A, B, C) of the Guidonian hand, commonly pitched around 261.63 Hz. The actual frequency has depended on historical pitch standards, and for transposing instruments a distinction is made between written and sounding or concert pitch. It has enharmonic equivalents of B♯ and D.

In English the term Do is used interchangeably with C only in the context of fixed Do solfège; in the movable Do system Do refers to the tonic of the prevailing key.