To decimate is merely to reduce by one tenth

Friday August 09 2019

A calendar. Although December is the 12th month of the year, its root, decem, does not come from any word which, in any language, means 12. PHOTO | FILE | NMG


What is it to decimate? I ask because of a headline on the letters’ page of the Daily Nation on July 31. A sub-editor had written: “Take action on cancer scourge before it decimates entire nation”. That is a major contradiction in terms. The sub-editor responsible raised the following question: Does to decimate mean to annihilate?

In other words, exactly how might cancer decimate an entire population? For instance, how might the whole of the Kenyan nation disappear? To reiterate, how is it possible to merely decimate an entire thing or system? I ask because to decimate is to reduce a number or a quantity only by 10 parts in 100 or by one part in 10.

The verb to decimate comes from decem, which is part of a Latin noun that stands for 10. But decem is also the basis of the word December, the English name for what was originally seen as the 10th month of the year. Indeed, the Latins, an ancient Euro-Mediterranean tribe, named the month irrespective of their own later knowledge of the year through the 12 parts nowadays known in English as “months”.

Yet even my statement may be puzzling. For, although December is the 12th month of the year, its root, decem, does not come from any word which, in any language, means 12. No, decem comes from a Latin word which refers, instead, to 10. The word decade, for instance, is a derivative which means 10 years.

Yet the puzzle is easy to solve if you realise, through your history books, that January and February, the first two months of the year, were added to the calendar only recently. Decem is, indeed, why even the mathematical system based on 10 is known adjectivally as decimal. Yet even that knowledge may be wholly puzzling because, to remind you, the word decimal does not refer to 12.

No, decimal belongs to the mathematical system known by the same adjectival term decem, which is part of a Latin word that refers, not to 12, but only to 10. The word thus raises major etymological problems. No, decem did not originally refer to the name of today’s twelfth month. Decem was the root only of the name of the tenth month.


Those facts raise at least one question: Why is it that the twelfth month, not the tenth, was what the language of England came to know as and continues to call December? The answer is that, at some point in their history, the native speakers of the language by which tiny England came to subdue a great deal of the human planet, had come to depend vitally on that word.

It is that December, the name of the month that we nowadays count as the 12th, was made to jump backwards to the position number 10 (decem). That raises quite another question: What do you mean by the verb to decimate? No, to decimate is not the same thing as to annihilate. To annihilate is to reduce a number (of something) to nothing.

However, the verb to decimate comes from the word nihil, through which English has also wangled its word nil. It belongs to the same family as the verb to annihilate, which means to reduce a system, a body or a number, to nil. To annihilate is, namely, to reduce to nothing.

To decimate, however, is not to reduce to nothing, not to annihilate, which literally means to reduce to nil, namely, to nothing. For its part, to decimate is to reduce only by one decem, namely, only by one tenth.

Philip Ochieng is a veteran journalist