For example, I am preparing a report for 1-10 of the month, then 11 to 20 and then 21 to 30. Is there any specific word for 10 days in English like weekly report which consist of 7 days?

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    The auto industry used to report sales using a "10-day period". – John Feltz Dec 14 '16 at 14:15
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    Some works of fantasy and/or science fiction use the term "tenday", but of course you probably shouldn't use that in a business report. – Doug Warren Dec 14 '16 at 14:54
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    From the full OED: decade definition 2b. A period of ten days, substituted for the week in the French Republican calendar of 1793 – FumbleFingers Dec 14 '16 at 16:37
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    @FumbleFingers I don't dispute the OED reference, but the common meaning of "decade" is now ten years, not ten days. – alephzero Dec 14 '16 at 17:02
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    @alephzero - did anybody say that "the common meaning" of decade is ten days? – user66974 Dec 14 '16 at 17:37

No single word is current usage for a period of ten days. A week covers a period of seven days, a fortnight covers a period of 14 days, but there is nothing in-between which can be considered current usage.

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    And in American English, fortnight is archaic enough that many speakers don't know how long it is anymore. – Joe Dec 15 '16 at 0:02
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    @Joe - you learn something everyday; I was amazed such a useful word could become archaic. In British English it's used all the time, as it's the typical length of a summer holiday. Then I had a look at the USA entry at this page en.wikipedia.org/wiki/List_of_minimum_annual_leave_by_country and I can now understand why it's not needed! – JonLarby Dec 15 '16 at 9:34

As others suggested, there is no English word that could mean "10 days". But the term "10 day" is broadly used for weather forecast and report. You can use

  • 10-day report for the first 10 days of a month
  • 10-day report for the middle 10 days of a month
  • 10-day report for the last 10 days of a month

Based on context, you can use the first/middle/last part of a month.


[Maryland Board of Physicians]

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Something not mentioned before,


or (more correctly)


This would mean there are 3 reports per month, which is accurate, and would make a reasonable fill-in for a single word meaning 10 days.

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    February; almost. :-) – MikeJRamsey56 Dec 14 '16 at 20:11
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    I am afraid you are confusing interval (or duration) with frequency. – michael.hor257k Dec 14 '16 at 22:15
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    This isnt really an answer to his question 'exactly', but it does fit his example, and may suit his needs better than the other answers. – colsw Dec 14 '16 at 23:41

Decade can be used to indicate a group of ten days in a sentence like "the first decade of the month", but "the first ten days of the month" is the expression more commonly used:

  • a group, set, or series of ten.


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    I would say it's ill-advised to use "decade" in this sense, as it would inevitably be read as meaning 10 years. – Hot Licks Dec 14 '16 at 13:52
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    -1. When decade is used with reference to time, I think the first two definitions in your link (cf years) dominate. – Lawrence Dec 14 '16 at 13:54
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    @Lawrence - no problem for the downvote, I am pleased you reconsidered your view. – user66974 Dec 14 '16 at 14:16
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    At least the German word "Dekade" means both, 10 days as well as 10 years. I think the same is possible with the English word "decade". – rexkogitans Dec 14 '16 at 16:55
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    @rexkogitans Not in British English. Apart from some technical uses in science and engineering (which refer to counting and measuring devices, but not specifically to measuring time), "decade" always means "ten years". – alephzero Dec 14 '16 at 17:06

The reason there is no satisfactory term is that we traditionally use a week which is inconsistent with the decade. Most people used non-metric units for most things before the French Revolution. The revolutionaries tried to metricate everything. Some were popular, like the metre, and some weren't, like the 10-day week and the 10-month year.

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A decad (note: not decade) is:

A group or set of ten.

Although not specific to days, if you divide a calendar month¹ in a set of three decads, it should be clear from context that it will refer to sets of ten days. For example:

For a higher resolution analysis, we divide each month in three decads, as shown in Figure 12, which shows...

The meaning in this context should be clear even to readers who are not familiar with the term decad. And who knows, you might set a trend ;-)

I have seen this usage in a context of climate and weather data analysis.

¹In climate models, a year consists of twelve months of exactly 30 days each. In this case, the division in three decads is exact.

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10 days in a metric week (called a dekade).

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    I am sorry, but I am confused. Please correct me if I am wrong. According to the link, "10 days in a metric week" seems to be equal to 7 days in a non-metric week that we normally use. How can 10 days in a metric week be 10 days in a normal week? How can you use the word in the OP's context? – user140086 Dec 14 '16 at 14:54
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    According to "metric time", 100 seconds make a minute, 100 minutes make an hour, 10 hours make a day, which means 1,000 minutes (our time) to make one single "metric" hour. Is that correct? Did the OP say he was measuring time according to this system or the ABT (Anglo-Babylonian Time) one? – Mari-Lou A Dec 14 '16 at 15:35
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    @Mari-LouA 10 metric days are exactly the same length as 10 "normal" days. It's still based on the rotation of the earth, anything else would be mad! 1 metric day = 1 normal day, 1 metric hour = 2.4 normal hours. – user198750 Dec 14 '16 at 16:19
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    No one would ever have any idea what you're talking about using this term. – MikeTheLiar Dec 14 '16 at 16:35
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    @w3d The question asked was, "Is there any word for 10 days in English?" I was only trying to supply an answers. I was not weighing in on the question of a metric week making any sense. :-) As James P pointed out, a 10 metric hour day can be handled but a 365.25 day year doesn't lend itself to being easily cast into a metric system. Orbital mechanics can be so messy. – MikeJRamsey56 Dec 14 '16 at 19:56

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