Subminor and supermajor

Origin of large and small seconds and thirds (including 7:6) in harmonic series.

In music, a subminor interval is an interval that is noticeably wider than a diminished interval but noticeably narrower than a minor interval. It is found in between a minor and diminished interval, thus making it below, or subminor to, the minor interval. A supermajor interval is a musical interval that is noticeably wider than a major interval but noticeably narrower than an augmented interval. It is found in between a major and augmented interval, thus making it above, or supermajor to, the major interval. The inversion of a supermajor interval is a subminor interval, and there are four major and four minor intervals, allowing for eight supermajor and subminor intervals, each with variants.

	diminished	subminor	minor	neutral	major	supermajor	augmented
seconds	D	≊ D	D♭	D	D	≊ D	D♯
thirds	E	≊ E	E♭	E	E	≊ E	E♯
sixths	A	≊ A	A♭	A	A	≊ A	A♯
sevenths	B	≊ B	B♭	B	B	≊ B	B♯

Traditionally, "supermajor and subminor, [are] the names given to certain thirds [9:7 and 7:6] found in the justly intoned scale with a natural or subminor seventh."