The other day I came across this page and found a phrase strange to me.

The Britannica Dictionary

a/one thousandth of a second = one one-thousandths of a second [= 1/1000 second]

The plural "s" confused me so much. Then, I checked the hundred entry of the same site.

one hundredth of a second = one one-hundredth of a second [= 1/100 second]

There is no plural "s" with "hundredth"! Now I'm relieved. The writer must have made a mistake. "One one-thousandth of a second" (without s) should be right.

But I checked a news site to make sure.

  • But Montgomery is the world record with a time of 9.78 seconds, one one-hundredths of a second faster than Greene's best time. (New York Post)

  • In one of the most thrilling 100-meter finals in Olympic history, Gatlin won gold by one one-hundredths of a second. (New York Post)

  • She finished fourth in the trials with a time of 11.11, just one one-hundredths of a second behind third-place finisher Lauryn Williams. (New York Post)

Now I'm totally confused again. Somebody help me (an English teacher from Tokyo). Both are OK? Why can you make it plural?

  • 8
    I agree with you- It shouldn’t be plural there.
    – Jim
    Jun 24 at 6:09
  • 1
    It looks odd, but the units are one thousandths of a second. Jun 24 at 6:43
  • 2
    @Jim I agree, "three one-thousandths of a second" would be correct since there are more than one of the units of time, however "one three-thousandths of a second" would be incorrect as there is only one of the units of time. It's a typo, even dictionaries aren't immune to typographical errors.
    – BoldBen
    Jun 24 at 6:47
  • 3
    @WeatherVane I disagree, the unit is one-thousandth of a second, it's only plural if there are more than one of them. Why should a thousandth be any different linguistically from a quarter, a tenth, a ninety-second, a hundred-and-fiftieth or any other fractional unit. It's a typo.
    – BoldBen
    Jun 24 at 6:52
  • 1
    @BoldBen the dictionary's examples are one thousandth of a second, and one one thousandths of a second. So the question "How many one thousandths of a second?" could be answered "One one thousandths of a second." Perhaps this is the difference between casual speech and a formal unit. "We were going at one mile per hour" and "the velocity was one miles/hour". Jun 24 at 7:01

1 Answer 1


This seems simple:

We need to distinguish between

a/one {[one] thousandth} = 1/1000

two {[one] thousandths} = 2/1000

a/one {two thousandth} = 1/2000

two {two thousandths} = 2/2000

  • 1
    It is more scholarly to address a challenged entry in a recognised resource with references supporting the counterclaim. If this is merely 'simple', migration should be the option. Jun 24 at 13:41
  • Edwin Ashworth: Does anyone say "one one-fifths of a second"? - No. The Britannica entry is simply wrong. Note the OP's comment after checking 1/100ths: The writer must have made a mistake. Indeed they must - and you agree. My examples show the correct use and I think you will agree. I offer you Samuel Johnson: "You may scold a carpenter who has made you a bad table, though you cannot make a table. It is not your trade to make tables.”
    – Greybeard
    Jun 24 at 14:17
  • Not my DV, by the way; I try to use balance. Jun 24 at 14:45
  • 1
    @Greybeard - I think Edwin's point was that if it's so basic as not to need references, then it should go to ELL. I've often wondered if there's a way to codify which things should be migrated and which not, and that seems like it might work. Jun 25 at 20:54

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.