In Harry Partch's theory of music, a chord or collection of tones whose just intonation ratios have all have the same denominator i.e. 8/5 5/5 6/5 7/5. The first three tones of an otonality are a major chord, the fourth is a funky flat minor seventh, and it goes on from there. Together with an equal number of utonalities they make up a Tonality Diamond.