In Harry Partch's theory of music, a chord or collection of tones whose just intonation ratios have all have the same numerator i.e. 7/4 7/5 7/6 7/7. The first three tones of an otonality are a minor chord, the fourth is a crazy sharp major sixth, and it goes on from there. Together with an equal number of otonalities they make up a Tonality Diamond.