[PW] "x" in Rx (prescription)

[Jeanne Schramm]

    The patron here is my mother.  She is wondering what the "x" in "Rx"
stands for. She asked her pharmacist and he has no idea.  I have found lots
of opinions, but I would like to get something from an authoritative source.
The main opinions surrounding Rx seem to focus on: 1. Latin for recipe, 2.
Corruption of the symbol for the Eye of Horus, the Egyptian symbol of
healing and good fortune,   3. Corruption of the ancient symbol for the
Roman god, Jupiter.
    The R originally was an R with a slash through the extended tail (and
the x was used when moveable type came along).
    Does anyone have any information as to which of these theories is the
one accepted in the medical and pharmacological communities?  TIA
    Jeanne Schramm, WLSC, W. Liberty, WV   26074