твирем

Etymology
There are two theories for the etymology of this word; Vasil Zlatarski and Mosko Moskov agree that it comes from, but Petar Dobrev says it comes from Proto-Iranic. So it means either the fourth or the ninth. Petar Dobrev's theory goes back to the Iranian-Bulgar theory. This is how Iranian words in the Danube Bulgar language are explained by this theory.

Numeral

 * 1)  nineth or fourth