Rebound

If you've ever wondered why razors seem to have more and more blades, I can sum it up in one word: hysteresis.

Hysteresis is the razor-blade engineers' theory about what happens to hair after a blade has been dragged over it. The word means "the lag in response exhibited by a body in reacting to a change in forces acting on it", which means, in lay terms, that if you pull on something and let go, it might not snap back as quickly as you'd expect. The engineers thought that this is what happens to a freshly razored hair: the blade pulls it out of the skin a little bit, and it doesn't snap back instantly, so a second, closely placed blade will cut off a bit more of the hair. Then when it does snap back, it's actually been cut to below the level of the skin. Result: closer shave.

And then eventually some marketing genius figured that if two blades are good, three are better, and five, of course, are the ne plus ultra of shaving. Until someone figures out a way to pack eight or ten into a single blade-holder.

Now, "hysteresis" looks very much like "hysteria" and "hysterical", doesn't it? And yet, bafflingly, there appears to be no etymological connection between the words. None at all.

"Hysteresis" is self-evidently Greek, and comes from "hysterein", "to lag behind". "Hysteria" and its relatives come from Greek "hystera", "womb". The nonexistent medical condition known as hysteria was thought to afflict women exclusively, and was attributed to, of all things, a wandering uterus, which, refusing to be nailed down where it belonged by the restorative power of a husband's dick (nuns and virgins were thought to be particularly prone), wandered around the body, causing trouble wherever it went. The usual cure for hysteria was, predictably enough, a good fuck, or, failing the presence of a husband (the only person who could provide such a thing, apparently), some stimulation. But not by the owner of the uterus! That would be indecent! Instead, a medical practitioner would provide "pelvic massage" to "hysterical paroxysm", otherwise known as masturbation to orgasm. Eventually, they started using vibrators. And then a little more eventually, women took matters (and vibrators) into their own hands.