This Shorter English Oxford Dictionary is showing her age.
Nonillion exemplifies the post-million divergence of numerical terms on the scales once referred to as British (long scale) and American (short scale) systems.
Giving in to the growing local use of the American system, the UK officially adopted the short scale terms in 1974.
I don’t recall learning this in school but must admit that is a long while ago now and my memory is also on a short scale when it comes to numbers and math.
So, how to remember the difference for future reference?
On the long scale each new term greater than million is one million times larger than the previous term ie. a billion is a million millions (10 to the 12th power).
Think of the terms rising in lots of 6 zeroes or “loooooong” scale.
On the short scale each new term greater than million is one thousand times larger than the previous term ie. a billion is a thousand millions (10 to the 9th power). Think of the terms rising in lots of 3 zeroes hence “short”er in scale.
PS If anyone knows how to use superscript in WordPress, I’d love to hear about it.