Root Number

Definition: the result of digital reduction — a single digit from 1 to 9 (or a master number), the base value for interpreting indicators. The ancient analogue is the Pythagorean technique of pythmenes (literally "roots"): the numerical values of the letters of a word were mathematically reduced to a single number from 1 to 9. The modern Russian term "root number" is a calque from popular literature, corresponding to "root number" in the English-language tradition.

[source: Pythagoras — Wikipedia (en)] Related: tsifrovaya-reduktsiya, chislo-zhiznennogo-puti, chislo-imeni.