They were "meaningless words" (ἄσημα ὀνόματα) potent to protect those who could speak them correctly, their power residing in their sound, so that they were ineffective if mispronounced.
In the 4th century comedy Lyropoios by Anaxilas, one character carries Ephesia Grammata inscribed on his belt.
[1] The best known Ephesia Grammata are a group of six words:[2] A version of this formula seems to be attested by a damaged inscription from Himera, Sicily, which must date to before the Carthaginian destruction of the city in 409 BC.
[3] The next earliest epigraphic evidence for the formula comes from the 4th century BC, and it continues to re-appear on magical papyri throughout the Hellenistic period.
: "λίξ: πλάγιος, καὶ λίθος πλατύς") as an ancient term for "Earth", and tetrax (τετραξός "fourfold") as the year (the four seasons), Damnameneus as "Sun" and aisia (αἴσιος "right, fitting, auspicious") as Logos.