June 1, 1999

crux

To verify that my spelling of "crux" was correct I looked it up in my dictionary. The etymology (which is something I never looked at until I found your web site) says that it's from a Latin word for "cross" or "torture." I'd love to know how this word went from "torture" to the meaning that I'm familiar with which is "an essential point."

As you note, the English word crux is from the Latin word meaning 'cross' (and the English word cross in fact comes from Latin crux, filtered through Old Norse and Old Irish) and hence, usually alluding to the one Jesus died on, 'torture'.

The main sense of crux in use today is your sense 'the central or pivotal point; essence' (example: "The crux of the 2000 versus 2001 debate lies in the controversial nature of the number zero" (The Atlantic Monthly, 1997)). This sense, first recorded in the late nineteenth century, is not the first one in English.

The original English sense of crux (excepting a direct reference to a religious festival of the Cross) is found in the early eighteenth century: 'a perplexing difficulty; problem' (example: "It was high time to be retiring for the night. The crux was it was a bit risky to bring him home" (Joyce, Ulysses)).

There are two explanations for the development of this sense, and both may have influenced it. The most obvious is simply that it is a figurative development of the 'torture' sense of the Latin word: a 'perplexing difficulty' is one that tortures the person who is trying to solve or explain it. A semantic parallel to the 'torture' sense of crux in English is found in the word crucify, now used chiefly to mean 'to torture; torment'.

On top of this, we can add the existence of a more directly relevant Medieval Latin phrase: crux interpretum, or the interpreters' cross, the torment of the interpreters, also referring to a perplexing difficulty of interpretation.

The link from the 'perplexing difficulty' sense to the current 'central point' is that a difficult issue will become an object of special attention, and thus will remain the focus of interest when simple issues have been dealt with.