Talisman

Part of speech: noun (n.)

1. A magical figure cut or engraved under certain superstitious observances of the configuration of the heavens, to which wonderful effects are ascribed; the seal, figure, character, or image, of a heavenly sign, constellation, or planet, engraved on a sympathetic stone, or on a metal corresponding to the star, in order to receive its influence.

2. Hence, something that produces extraordinary effects, esp. in averting or repelling evil; an amulet; a charm; as, a talisman to avert diseases. Swift.