Rx - The eye of Horus

There are several explanations for the symbol Rx.

The symbol Rx is derived from the major lines in the symbol of the Eye of Horus. Horus was an Egyptian god, the god of Nekhen, a village in Egypt, and god of the sky, of light, and of goodness. He was the son of Isis, the nature goddess, and Osiris, the god of the underworld. Osiris was murdered by his evil brother Seth, the god of darkness and evil. Horus sought to avenge his father's death by challenging his uncle Seth to a firght. Seth cut out Horus's eye, but Thoth, a god associated with wisdom and compassion, magically restored the eye. Horus did defeat Seth, finally. The eye of Horus consisted of the sun and the moon, and it was the moon eye that was damaged. This explained the phases of the moon-the waning of the moon was the eye being damaged and the waxing, the healing. The eye of Horus became a powerful symbol of healing in the eyes of the Egyptians. In Egyptian art, the eye of Horus strongly resembles the modern Rx of the physician. Horus's eye, also called he wadjet eye, became a symbol for health.

Anothet common explanation is that it comes from the Latin word recipi or recipere, which means "take" and is abbreviated as Rx. The symbol can also be traced to the sign of Jupiter, which was found on ancient prescriptions to appeal to the Roman god Jupiter.