Musical note commonly), a double sharp sign on a key signature with a single sharp indicates only a double sharp, not a triple sharp. Assuming enharmonicity, many accidentals will create equivalences between pitches that are written differently. For instance, raising the note B to B is equal to the note C. Assuming all such equivalences, the complete chromatic scale adds five additional pitch classes to the original seven lettered notes for a total of 12 (the 13th note completing the octave), each separated by a half-step. Notes that belong to the diatonic scale relevant in the context are sometimes called "diatonic notes";
Diatonic scale The pattern of elementary intervals forming the diatonic scale can be represented either by the letters T (Tone) and S (Semitone) respectively. With this abbreviation, major scale, for instance, can be represented as The major scale or Ionian scale is one of the diatonic scales. It is made up of seven distinct notes, plus an eighth that duplicates the first an octave higher. The pattern of seven intervals separating the eight notes is T–T–S–T–T–T–S. In solfege, the syllables used to name each degree of the scale are "Do–Re–Mi–Fa–Sol–La–Ti–Do". A sequence of successive natural notes starting from C is an example