German sixth chord

A German sixth chord is a tetrad comprising a root, major third, fifth, and augmented sixth. In meantone (including 12edo), on which traditional tonal harmony is built, the German sixth chord is essentially just, tuned identical to the harmonic seventh chord:

• 1 – 5/4 – 3/2 – 7/4 with steps 5/4, 6/5, 7/6.

English Wikipedia has an article on:

Augmented sixth chord #German sixth

Alternatively, a 5-limit interpretation is given as 128:160:192:225.