C

C is pitch class 0 — the reference step from which the other eleven are counted in this catalog. In equal temperament it is one twelfth of the octave, the same size of step as every neighbor, yet it is the conventional starting letter of the chromatic and diatonic namings used here.

As a pitch class it is not a key and not a mood. It names a class of pitches an octave apart: great C, middle C, and every C above or below belong to the same class. On staff or keyboard it is the natural white key between B and D.

In major-triad grammar C is the root of C major (C–E–G), the perfect fifth of F major (F–A–C), and the major third of A♭ major (A♭–C–E♭). Alone it stays a single step. Three notes that form a recognized major chord may open a vessel offering; this page does not.

Also known as C natural · Do