Isopsephy — from the Greek isos (equal) and psephos (pebble, used in counting) — is the Hellenistic equivalent of gematria. Each letter of the Greek alphabet carries a numerical value, and practitioners summed these to find words or phrases of equal value, interpreting the equivalence as revealing hidden truth.
Isopsephy was widely used in ancient Greece and Rome for oracular purposes, love charms, and political commentary. Writers embedded isopsephic meanings in poetry and inscriptions, creating layers readable only to the initiated.
The practice influenced early Christian numerology, including interpretations of the number 666 in the Book of Revelation, which scholars read as an isopsephic reference to a specific name.