In the theory and practice of music, a fifth interval is an ordered pair of notes that are separated by an interval of 6–8 semitones. There are three types of fifth intervals, namely * perfect fifths (7 semitones), * diminished fifth (6 semitones), and * augmented fifth (8 semitones). After the unison and octave intervals, the perfect fifth is the most important interval in tonal harmony. It is highly consonant. Its implementation in equal temperament tuning is highly accurate, unlike the major third interval, for example. As explained below, it is used to generate the chromatic circle and the cycle of fifths, and it is used for tuning string-instruments. It is a constituent interval for the fundamental chords of tonal harmony. (en)