Rx (prescription)

I found several different theories about the origin of this symbol "Rx" used by doctors before a prescription. Is it an abbreviation? Is it some ancient chemical symbol?

Several origins sound less credible. One source said that Rx is a corruption of the symbol for Jupiter and that a prayer to Jupiter would speed healing. That doesn't make sense to me since Jupiter (also known as Jove) was the god of the sky and thunder and king of the gods in Ancient Roman religion and mythology and not associated with healing.

I couldn't find a symbol for the god, but the symbol for the planet looks like an odd 4 and is said to represent an eagle, which is Jupiter's bird.

Another theory is that the Rx symbol evolved from the Eye of Horus, an ancient Egyptian symbol associated with healing powers. This has a bit more believability because pharmacy has been around for thousands of years and the first recorded prescriptions were etched on a clay tablet in Mesopotamia around 2100 B.C. There were the equivalent of drugstores in Baghdad in the eighth century A.D.

The problem is that the Eye of Horus (also known as wadjet, wedjat or udjat) though it is an ancient Egyptian symbol of protection, royal power, and good health, doesn't look like the Rx.

The most likely origin is that this symbol seen on doctor’s prescription pads and signs in pharmacies is derived from the Latin word “recipe,” meaning “take.”  The word recipe has had the same function from the 13th through the 17th centuries. The two letters were a 19th-century way of easily reproducing a 16th-century symbol - the letter R with a line through its slanted leg.
℞  that meant the "R" is functioning as an abbreviation - not an X.
It wasn't till around 1911 that "Rx" came to be used as meaning the the noun "prescription." A recipe associated with cooking came into being in the early 17th century, which is when America’s earliest drugstores came into being in big cities. The first college of pharmacy in the United States was founded in 1821 in Philadelphia.

Today in America, the centuries old mortar and pestle - tools of the trade - is often used by pharmacists as an industry symbol along with Rx.