Why do magicians say “hey presto”? Well, as anyone who’s ever had piano lessons will likely know, presto means “quickly” in Italian, and so has long been used by conjurors to draw attention to some sudden, magical appearance or disappearance on stage. Shazam was originally Captain Marvel’s catchphrase, coined so that it gave him the wisdom of Solomon, the strength of Hercules, the stamina of Atlas, the power of Zeus, the courage of Achilles, and the speed of Mercury. Hocus-pocus is thought to be a corruption of Hoc est corpus meum, “this is my body,” words used in the Latin Catholic Mass. But abracadabra is a bit of a mystery.

One theory is that it comes from ancient Aramaic, and might once have meant something like “I create as I speak,” perhaps a phrase lifted from some ancient religious text. Alternatively, it might be a mangled corruption of the Hebrew words ab (“father”), ben (“son”), and ruach acadosch (“holy spirit”). Or perhaps it derives from abecadarius, a Latin word essentially meaning “alphabetical order,” in which case it might once have implied putting everything magically back in its correct place or order. But whatever its etymology might be, there is one thing sets abracadabra apart from all the other “magic” words—it was once believed to be genuinely, miraculously, magic.

Back in the 3rd century, a Roman scholar and physician named Quintus Serenus Sammonicus wrote a lengthy medical manuscript called De medicina praecepta, or “The Rules of Medicine.” Sammonicus’s cures included pouring a mixture of ox bile and sheep’s urine into the ear to cure earache, wrapping the head of a delusional patient with the bloody lungs of a recently slaughtered sheep, and treating one type of recurrent fever by placing the fourth book of Homer’s Iliad beneath a patient’s pillow. But to treat full-on malarial fever, he explained, you really had to resort to magic.

In chapter 51 of his textbook, Sammonicus advises that any patient suffering from a fever should be given a piece of papyrus, at the top of which is written the magical word ABRACADABRA. Beneath that is written ABRACADABR, with the last letter A omitted. Beneath that is ABRACADAB, with the final R now gone. Then ABRACADA, ABRACAD, ABRACA, and so on, until on the bottom line is written nothing more than a letter A:

ABRACADABRA
ABRACADABR
ABRACADAB
ABRACADA
ABRACAD
ABRACA
ABRAC
ABRA
ABR
AB
A

The patient should then wear this inverted pyramid of letters on a string around their neck, where it would act like a funnel, channeling the illness out of their body. Whether Sammonicus’s cure worked or not is beside the point (derived from a New World crop, it would be another millennium before European doctors began using quinine to treat malaria). But it was his use of the seemingly ancient word abracadabra as a talisman-like charm that eventually led to its long association with magic and sleight of hand.

Medical textbooks in the Middle Ages, more than a thousand years after Sammonicus’s writing, were still listing abracadabra as a magically curative word, but as time went by and as medical treatments improved its use steadily dropped into pseudoscience—from where it was picked up by magicians and performers. (It was still being used in the 17th century; during the London Plague in 1666, Daniel Defoe noted that “[the possession of the disease] was to be kept off with crossings, signs of the zodiac, papers tied up with so many knots, and certain words or figures written on them, as particularly the word Abracadabra, formed in triangle or pyramid, thus:" showing the same pyramid as above.) By the early 19th century, conjurors were calling on abracadabra to magically assist them in their tricks, in the same way that a feverous patient would once have called on it to assist them in their recovery.

The word’s association with quack medicine and pseudoscience has endured however, so that abracadabra is still sometimes used as another word for anything superstitiously held to have magic powers, or as another word for nonsense language or mumbo-jumbo. But it’s as a magic word that it remains best known today—though perhaps not as magic as it once was.