by Fabricio Jimenez

A few years ago, back when I was a Summer Student at CERN, me and other physics students had some debate on the origins of the word “hysteresis.” We were just coming back from CinéTransat – an open-air cinema at La Perle du Lac park in Geneva, and having a random chat until Sabina jokingly accused Josefa of being hysteric, for a reason I can’t remember right now. From there, they started a discussion on how the word “hysteric” was related to “uterus” (at some point in the past, hysteria was defined as a psychological disorder related to the organ), and to “hysterectomy” (the removal of the organ). Very naïvely, I added what I once heard and believed, that “hysteresis” may also be part of this family of words; looking so similar, I suspected that this was the case, but haven’t checked by myself why. Sabina and Josefa with their smartphones quickly jumped in to refute my claim, citing the different meanings of the respective words: “uterus” comes from the Ancient Greek word for womb, whereas “hysteresis” from the version of “delay” or “late” in the same language. Sabina guilefully added that she “broke a myth” for me.

Now, there is something straightforward for physicists: the connection between hysteresis and delay. A system is said to present hysteresis if in a given moment its state is lagged with respect to the effect that produced such state; in this context it is often said that the system “keeps a memory” from the past. A common example appears in electromagnetism: in the presence of an external magnetic field, a ferromagnet gets magnetized (i.e. generates its own magnetic field because of the external one) and such effect stays even after the external magnetic field is not present anymore. Moreover, the intensity of the magnetization does not follow exactly the one from the external field, but it is instead delayed with respect to it at any given moment.

When I came back home scratching my head because of the origin of these words, my research was not very fruitful. I could only point out that the Ancient Greek roots of the words looked similar, but the meanings differed: hysteria comes from the word for uterus “husterá” (ὑστέρα), whereas hysteresis (ὑστέρησις) comes from “delay” – “husteros” (ὕστερος). At the time I went on to ask Mina, a Greek friend and a physics student, about my quest for which she had no immediate answer. After some days, however, she came with an answer from her uncle (who has knowledge in the ancient language) that pointed very much towards a relation between the words.

Before going to the dénouement of my story, I have to say that for the purpose of writing this blog post I relaunched my hysteresis-hysteria search in order to confirm what I’ve got in the past. This included discussions with several members of the Network, a few of which have taken Ancient Greek courses at some point. The crucial information finally came from a friend of Cecilia, who’s a doctoral student in Philology and Linguistics in her university.

The explanation from Cecilia’s friend reads something like this: hysteresis comes from “husteros,” that means “additional, posterior” but also “more external” and from here the word “uterus” was used to designate the pregnant belly, or the “more external part” of the body; in ancient times, the knowledge in anatomy was not as precise as it is today. In a different version, Mina’s uncle said that the relation was given by the delay with which the placenta is expelled after a woman gives birth to a child; the placenta and other organs were accordingly named after this peculiarity. Either way the words are linked!

unnamedIn my attempt to “glue a myth back together,” I remembered a beautiful book written by Isaac Asimov, that my dad gave me when I was about 12. “Words from the Myths” tells many fascinating stories on how commonly-used words have their roots in ancient myths. This book sparked my interest in knowing how words are originated – I strongly recommend you to read it!