You searched for: “onomancy
nomancy, onomancy (s) (noun) (no pl)
Divination by the letters of a name: Onomancy is known to assess the number of vowels in a name, or to interpret the sum of the numerical value of the letters.
onomancy, onomomancy (s) (noun) (bo pl)
Divination or fortune-telling with names: Onomancy is a system of prophecy using proper names based on a subject's given name, and was popular in the Late Middle Ages.