I commented the other day on the essay in The New York Times by the violist who despises the use of crescendo to mean "reach a climax," and, not surprisingly, the essay has drawn considerable attention at Language Log. One comment in particular by J.W. Brewer is instructive:
Is there a short-form name for the stock error that professional-jargon technical meanings ought as of right to control the extended/metaphorical meaning of the same words when used in different contexts by non-members of the relevant guild? This guy also has the the-true-meaning-is-controlled-for-all-time-by-the-original-morphological-derivation-of-the-word-in-some-foreign-language error.
So there are two problems conflating here, the insistence on expert meaning and the etymological fallacy.
Experts are entitled to their vocabulary, and other experts or would-be experts are expected to master it. If you are playing in a band or orchestra, you had better understand the technical meaning of crescendo. But words do not stay put; they slip their leashes and jump the fence. Crescendo, like it or not,* has taken on a non-specialist sense of climax.**
We see these non-specialist senses developing all the time. Remember the vogue fo parameter? I trust that mathematicians still use it for "a quantity or constant whose value varies with the circumstances of its application." And I trust that it is still used by non-specialists for whom "boundary" or "limit" conveys inadequate pomposity.
We also see considerable drift from etymological origins. People who carp and cavil about decimate used in any sense other than "reduce by one-tenth" lost that battle to the metaphorical sense as far back as the seventeenth century. Time to retire the legionaries.
Over time, as with climax and decimate, non-specialist or metaphoric senses of technical terms become accepted and unremarkable. In writing about grammar and usage, I sometimes remark on how far my writ extends, and I am confident that you do not imagine that I have judicial authorization to bind and loose. Or desire it.
I sympathize with Miles Hoffman, the author of the Times essay. I was in my high school band and have played piano and organ for years; crescendo for climax hurts my ears, too. But claiming that the looser usage injures the language is hyperbolic and futile. That barn door has been open for a long time.
Besides, when someone uses crescendo in the loose sense, you understand what it means, don't you?
*And, as always, if you don't like it, don't use it.
**One of the commenters at Language Log points out that climax itself, which originally meant, from the Greek word for "ladder," a "rhetorical figure of speech consisting of propositions rising in effectiveness," has also drifted from its first technical sense.