If you pay attention to such things, at some point in your life you’ve probably heard a speaker of British English use the phrase “thousand million” (or perhaps you’ve seen it in print). If you’ve had someone willing to translate, or you’ve been able to look it up, you might have been informed that in the US we say “billion” for a one followed by nine zeroes (1,000,000,000; known to its scientifically inclined friends as 109), but that in the UK and most other countries of the Commonwealth they call this a “thousand million.” In the UK “billion” is reserved for a one with twelve zeroes (1,000,000,000,000; 1012) — which in the US we’d call a “trillion.”
It turns out that, according to standard usage, this is wrong: we should use the same terminology, regardless of which flavor of English we’re using or on which side of the Atlantic we’re standing — and the correct variation is the one described as “American” above.
While I’ve long been aware of the ‘billion/thousand million’ distinction, I’ve never had to edit anything that actually used it. But I only recently learned that the distinction is no longer valid. Why is this the case?
Speakers of English don’t have to put up with regulatory bodies which define what the “official” version of a language is — which words are acceptable, how to spell them, how to pronounce them, what grammar is acceptable, etc. In English, all these things are a matter of convention and tradition. The “rules” of our language are only an accumulation of what most speakers and writers, over time, consider “correct.”
However, there are certain groups that are able to throw a lot of weight around when it comes to what is acceptable “standard English.” International standards bodies and government agencies are often ignored in day-to-day living, but in certain realms — in this case, science and statistics — they carry a great deal of clout.
In scientific work, people need to communicate data quickly and accurately, regardless of the language used. That’s a large part of the reason why we have the SI: weights and measures translate with no trouble. It’s a boon not just to science, but to everyday commerce.
While most of us (in the US) don’t use SI units for typical transactions on a daily basis, they’re still all around us. Of greatest importance might be the standard SI prefixes (kilo, giga, mega, etc. — I posted about one of them in particular some time back). While the metric (SI) prefix names don’t change from language to language, the local names for large numbers sometimes do.
Over the centuries (much of this is pre-SI, which dates officially to 1960), two main sets of names developed for these numbers. The British developed one system, which eventually came to be known as the long scale. The French developed another system, eventually known as the short scale (which the Americans somehow adopted).
The short scale uses terms familiar to Americans: million, billion, trillion, quadrillion, etc. The long scale uses those terms as well, but adds steps between them. One million is one million on either scale, but an American billion is one thousand million (or a milliard); an American (short scale) trillion is one billion; an American quadrillion is one thousand billion (or a billiard). And so on. The farther along these scales you go, the farther apart the numbers become: while a short scale and long scale billion differ by 103, a short scale and long scale quadrillion differ by 109, and the disparity keeps growing. (If you’re not following my text explanation, this wiki entry and table might help clear things up.)
It seems to me that simplicity was bound to win out in the end: the short scale follows a logical progression which allows an educated person to guess at the next term, using common Greek and Latin number prefixes. Knowing billion, trillion, and quadrillion lets one assume quintillion, sextillion, and septillion are coming up.
The long scale requires additional steps. A user has to remember that once they’ve gone above millions, there’s always the stutter-step of adding “thousand” before moving to the next label. So thousand million, then billion; thousand billion, then trillion; and so on. The alternative is to remember the other stutter-step of giving each label the “-ard” suffix before moving on: million, milliard; billion, billiard; trillion, trilliard; and so on.
While the long scale and short scale have only been known by those terms since the 1970s, the difference has existed for centuries. As I noted earlier, the French used the short scale, while the British used the long scale. For reasons not entirely clear to me (do the research and report back, if you’re so inclined) the French changed their standard usage in 1961, shifting from short to long. The British, on the other hand, went in the other direction (from long to short) in 1974.
Which brings us back to the point: since late 1974 the short scale (billion, not thousand million; and so on) has been official and correct usage in government communications in the UK. The BBC and the rest of the media in the UK followed fairly quickly. Since then, one billion has meant the same thing in both versions of English. Even Oxford has been moving toward simplification: the OED still gives the older British definition of billion precedence, but the more fluid and more-frequently updated online version tags the “million million” (1012) version as “dated.” Curiously enough, while Oxford includes milliard, the only definitions it presents for “billiard” have to do with the game played with long sticks and resin balls on a green velvet table.
That’s it in less than 1000 words: a billion is a billion is a billion is not a thousand million, whether you’re in the UK or the US.
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Notes: Of course, neither life nor language is ever as simple as it should be. Because British use shifted from one scale to another (and French usage, in the other direction), one has to be especially careful when dealing with historical documents. A billion in 1972 (or 1942) might not be the same as a billion in 1976. Modern sources with large numbers primarily use SI units, so confusion is automatically limited, but colloquial sources aren’t always as precise.
SI has its quirks and surprises too, though: I’ll bet you didn’t know, for instance, that the liter is not actually a fully sanctioned SI unit. The things I stumble across during the research process are what keeps it interesting for me.
For a little further reading: it was this letter and response in a recent issue of Science News that got me curious about all this in the first place.