A point of clarification

And this has nothing to do with anything, but it does set my teeth on edge:

If you say something has a “three-fold increase”, it does NOT mean that you are multiplying the increase by three or that the increase is 300%.

Take a piece of paper. Fold it in half. You have two layers. Fold it again, and you have four layers. Fold it a third time, and you get EIGHT layers.

That’s right: “something-fold” is supposed to be exponential, not multiple.

And really, it seems to be such a small thing, but it makes me a little crazy. Please, use your folds wisely.

This rant was inspired by a single line of urk in this very excellent article on HOW healthcare has become so goshdarn expensive.

Dawn Written by:


  1. May 29, 2009

    Every dictionary definition I’ve found so far (five or six) disagrees with you on that. They all say threefold means either “having three parts” or “three times as many or as much”.

    • May 29, 2009

      I KNOW! And it makes me CRAZY!!

      I’m sure it started with some math-a-phobe freaking out at having to explain what an exponent was, and then he ended up rewriting the definition to appease his own widdle scaredy pants…

      Serious and for real, three-fold is 2^3. Really. That’s what it SAYS. Three FOLDS.

      • Anonymous
        May 31, 2009

        Sorry, the roots of -fold as a multiplicative suffix have origins going back to antiquity, before exponents were even formalized, serious and for real. Even mathematicians use it thus: consider when they speak of “threefold symmetry” for example.

        And then there’s the fact that the word multiply comes from Latin multi- — many — and plicare — FOLD. Will you next tell us that “multiplication” really means exponentiation?

        To understand this, consider that there may be many ways of folding something besides in half. 🙂

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