A co-worker tonight used the word "recalcitrant", and of course I immediately began to wonder where it might have come from, and more or less at the same moment
she began to wonder the same thing, knowing that I was pretty much obliged at that point to write about it. And here it is!
My first conjecture was that it pretty much had to be related to "calculus" somehow, though I wasn't quite sure how. (I thought I had discussed "calculus" before, but as it turns out, I'd only made a passing reference to it,
here.) It seemed likely, if not certain, that all the "-calc-" words in English were related somehow, and therefore "recalcitrant" had to be part of the extended family.
"Calculus" means "stone", or, more specifically in this instance, "pebble", because originally pebbles were used as markers in calculation (another "-calc-" word!). And why "pebble" and not "stone"? Because, yet again, we have that omnipresent "-ule" ending, this time in the Latin formation "-ulus", and,
as you might recall, "-ule" and "-ula" are diminutives. A "calc", therefore, ought to be a stone, and a calculus is a little one.
But there isn't any such word as "calc" in English. There is, however, such a word as "calx", and it means...not quite what you might have thought: it's the detritus left after stones (and metals) have been burned as thoroughly as they can be. It's mineral oxide.
Okay, let's take another tack. "Calcium" obviously starts with "calc-" and, being a stone or the component of one, must have the same root, and so it does. Limestone is a mineral which consists largely of calcium carbonate, and another word for "limestone" is..."calx".
"Calx" comes from Greek "khalix", "pebble" (there's that word again). Now, calcium carbonate is the principal component of chalk, and where do you suppose the word "chalk" came from? Yeah, "calx" again.
So what are we to make of "recalcitrant"? My first thought was that it had something to do with being as immovable as a stone, because "recalcitrant" means "resisting control", or, more broadly, "stubborn". But the truth is even more interesting (and confusing), because Latin had a verb, "calcitrare", "to kick, to strike with the heels", and from that the verb "recalcitrare", "to be disobedient", meaning that "recalcitrant" actually translates as "kicking back (against authority)".
But why does "calcitrare" mean "to strike with the heels"? Because in Latin, "calx" also meant "heel". And why does that one bone of the body--a bone which, like all the others in the human body, is also made up largely of calcium, by the way--get the same name as limestone and, by extension, a rock or a pebble, while none of the others did?
Oh, I don't know. I can't know everything. (It may be the case that Latin simply had two different versions of "calx", completely unrelated to one another. It's common enough in English, and other languages besides--even Indo-European had multiples of some words.)
But here's something interesting: the verb "inculcate" is also from "calx", meaning "heel": it's from Latin "in" plus "calcare", "to tread (with the heel)", therefore "to stamp in: to make an impression on", which is just what you do when you inculcate your beliefs in someone.
And one more: though there isn't a "calc" in English, there is a "calque", derived from, obviously, French. "Calque" means "tracing paper" in French (which is to say something that takes an impression), but in English, it's a metaphorical tracing: it means the borrowing of a word or phrase by translating it exactly from the other language, as in "masterpiece", taken whole from German "Meisterstück".