Abraxas is a mystic word made up of Greek letters. It is referred to as Abrasax in some sources, which may have been the earlier spelling. The word was believed to have magical properties and was inscribed on ancient charms and amulets.

In the 2nd century AD, the early Gnostics personified the word as their Supreme Deity. Abraxas is symbolized on ancient talismans as the head of a cock on the body of a man with a whip in one hand and a shield in the other. The symbol is also engraved on gemstones called the Abrasax stones. (1)

Abraxas-gems are engraved stones of varying material and form upon which this word appears, either alone or with other names of God, and in connection with mystic figures and groups of letters. The most frequently encountered Abraxas figure is a human form with a fowl’s head and the extremities of a serpent, carrying in the one hand a shield and in the other a whip. These Abraxas-stones, especially those which from their material are used for superstitious practises, are also of interest from the standpoint of Judaism, inasmuch as they often bear Hebraic names of God: Iao, Sabaoth, Adonai, Eloai. (2)

References: (1) https://www.jewishencyclopedia.com/articles/633-abraxas (2) https://mythology.net/greek/greek-concepts/abraxas/ (3) https://symbolsage.com/abraxas-symbol-meaning/