Just a few days back, I finished perusing the little grammar book Things Your Grammar Never Told You. It’s an interesting book, and I’ll get around to posting more about its strengths (and of course, its weaknesses), but I have a small qualm for the time being.

On page 54, Scharton and Neulieb talk about usage and shifts in meaning, specifically mentioning the word decimate:

Sometimes confusion about a word’s denotation occurs when people use the word in a more general sense than its original meaning warrants. Generalized use can stretch a word’s meaning until it sags like an old sweatshirt, comfortably covering more and more, revealing less and less, and doing its job in a particularly unattractive way. […] As far as some political writers are concerned, the verb decimate means “to reduce drastically.” Decimate, which is related to the word decimal, means “to eliminate one in ten.”

Later, in a glossary of usage, there is an entry for decimate, annihilate:

Note that the Latin root, deci-, is the same as in decimal, a system of numbers based on ten. Decimate means to “reduce by ten percent”; it refers to the bloody practice of slaughtering one captured soldier in ten. That’s bad but not as bad as annihilating, that is, wiping out everyone.

I was, to say the least, disappointed at seeing this.

The truth, of course, is that decimate does not merely mean “to take one out of ten,” and it very frequently means “to reduce dramatically.” Moreover, this error is an example of a fallacious appeal to etymology, and linguist Ben Zimmer  gives very convincing evidence about why it should not be defined as such:

Saying that the “real meaning” of decimate is ‘reduce by one-tenth’ aptly illustrates the “etymological fallacy” — the notion that we have to go back to the usage of a bygone era, and perhaps even a different language, to divine the “true” sense of a word. Decimate entered English around 1600, with reference to the Roman army practice. Around 1650, the Earl of Essex tried to revive Roman “decimation” to keep the peace in Ireland, but subsequent use of the word decimate in the “one-tenth” sense invariably referred back to the Roman era. And by 1663 the usage of decimate had already expanded to mean “to destroy or remove a large proportion of,” according to citations collected in the Oxford English Dictionary.

For nearly three and a half centuries, then, virtually every use of the word decimate has been in this extended sense, except when referring to the harsh old Roman practice. And these days such references seem limited to complaints about the word itself.

This error, in my opinion, is indicative of a deeper problem that seems to be entrenched in most grammar texts. Yes, grammar is about rules, tendencies, and to a degree conformity to the standards that your readers  will expect you to have, but it is not about proscriptions and dictums handed down from on high. While I think this text does better than some others (like the highly overrated Elements of Style), its propensity to spout the same old grammatical canards is disheartening. If someone can show me a grammar text that doesn’t do this sort of thing, I would be delighted.