undecimal

Unfortunately, here on planet Earth, with its decidedly undecimal sidereal year of 365-and-a-quarter days, that is just not going to happen.

Undecimal neutral thirds appear in traditional Georgian music.

Based on its positioning in the harmonic series, the undecimal neutral third implies a root one whole tone below the lower of the two notes.

The greater undecimal neutral second may be derived from the harmonic series as the interval between the tenth and eleventh harmonics.

It distinguishes between and closely matches all intervals involving up through the 12th overtones, with the exception of the greater undecimal neutral second (11:10).

The 11th harmonic and intervals involving it are less closely matched, as illustrated with the undecimal neutral seconds and thirds in the table below.

It is the smallest two-digit prime number in the decimal base; as well as, of course, in undecimal (where it is the smallest two-digit number).

In the Sabat-Schweinitz design, syntonic commas are marked by arrows attached to the flat, natural or sharp sign, septimal commas using Giuseppe Tartini's symbol, and undecimal quartertones using the common practice quartertone signs (a single cross and backwards flat).