There are many theories behind its meaning, but the most acceptable is that "R" is "recipere" and "x" is the "sign of Jupiter" (chief God of Romans)
Some note its similarity to the Eye of Horus. Horus was an Egyptian god. The eye of Horus was a symbol used in Ancient Egypt to ward off evil and used for good health.
The R part of the symbol stands for the Latin “recipe”, the imperative form of “recipere”, which means “to take” or “take this”. The X part of the symbol is derived from the symbol for the Roman God, Jupiter. It represents a prayer or invocation to Jupiter that the treatment would result in a cure, with divine help. So Rx really means “take this and pray”. It goes back to ancient Roman times when people believed that if you were sick, it was because you had offended the gods and the illness was retribution.
The eye symbol is easily recognized as the letter "R." In recent times, the use of "R," followed by "x" to indicate an abbreviation, has led to many new abbreviations, such as "Hx" for history, "Dx" for diagnosis, Bx for biopsy, Cx for cervix, Hx for history, Ex for examination, and so on.
Generally, any medical prescription has 4 parts;