Wikipedia
Ragisma
In music and tuning, the ragisma is an interval with the ratio of 4375:4374, ≈0.396 cents (a superparticular ratio). It is usually defined as the difference between the septimal minor third (7:6) and two Bohlen–Pierce small semitones (27:25 ). It is also the difference between minor Bohlen–Pierce diesis (245:243) and septimal semicomma (126:125).