Septimal tritone

They are also known as the sub-fifth and super-fourth, or subminor fifth and supermajor fourth, respectively.

[3][4] The 7:5 interval (diminished fifth) is equal to a 6:5 minor third plus a 7:6 subminor third.

The difference between these two is the septimal sixth tone (50:49, 34.98 cents) Playⓘ.

The lesser septimal tritone is the most consonant tritone when measured by combination tones, harmonic entropy, and period length.

[5] Depending on the temperament used, "the" tritone, defined as three whole tones, may be identified as either a lesser septimal tritone (in septimal meantone systems), a greater septimal tritone (when the tempered fifth is around 703 cents), neither (as in 72 equal temperament), or both (in 12 equal temperament only).