Also an
abbreviation (
perhaps) used by
pharmacists.
(There are the days when I wish that I could do
bilingual hard links so that I could remark that in
Britain they're called
chemists, but ah well...)
It may come from the Latin word recipere meaning ``take, thou'', or it may come from the symbol for Jupiter, or it may have come from the eye of Horus (or udjat), which had an eye with an x below it.