When talking about a year long interval I can say "annual" to mean "yearly". For example, "the annual yield is", "the interest rate is 25% per annum", or "the annualized interest rate is 25%" if the original rate given is daily/overnight rate.

Is there a similar Latin-based word for other periods, especially for a single day? I can say "per diem" where I would say "per annum", but what about other use cases?

"If you invest $10000 in our payday lending company, you can expect ??? gains of $15" or "Short on cash? Borrow from us! Our ???ized interest rate is only 1%!"

I know there are "diurnal" and "nocturnal", but they usually mean "day" and "night" as in "when the sun is up" and "when the sun is down".

  • 1
    Why would you purposefully look for a Latin origin word? That's backwards.
    – William
    Commented Oct 28, 2015 at 0:41
  • 2
    @William I won't exactly call it backwards, but it is exactly opposite to the aim of the Anglish project
    – March Ho
    Commented Oct 28, 2015 at 2:28
  • @William: Quidquid latine dictum sit, altum videtur.
    – Dan
    Commented Oct 28, 2015 at 6:38

5 Answers 5


"Quotidian" (if it really has to be a Latin-based word).

  • 2
    Has it ever been used to describe interest rates? Or are interest rates only ever "daily" or "overnight"?
    – Alexey
    Commented Oct 27, 2015 at 13:56
  • 2
    I would not say "never", but it is certainly not common.
    – fdb
    Commented Oct 27, 2015 at 13:59
  • 3
    Fun fact: in Italian, newspapers are called "quotidiani", i.e. literally "dailies". (The other word for them, "giornali", related to the English journal/journalism is also related to that meaning).
    – UncleZeiv
    Commented Oct 27, 2015 at 18:36
  • 1
    @UncleZeiv The same applies for French, and I presume other Romance languages too.
    – March Ho
    Commented Oct 28, 2015 at 2:26

Per-diem is a Latin expression still used in the English language:

  • by the day; for each day.


Example sentences:

  • The popular governor collected the per diem allowance from April 22

  • A spokeswoman said that a separate state board sets per diem payments.

  • The six-member commission angered many lawmakers when it voted last year to cut pay and per diem by 18%.

  • Tax-free per diem allowance to defray living expenses away from home.

  • A budget that puts two players per hotel room, and offers a $30 per diem and salaries that top out at $26000.


  • 2
    From the question: "I can say "per diem" where I would say "per annum", but what about other use cases?" Commented Oct 27, 2015 at 14:17
  • Here are a few usage examples: sentence.yourdictionary.com/diem
    – user66974
    Commented Oct 27, 2015 at 14:21
  • I would suggest that "per diem" belongs to specialised banking/financial/fiscal usage.
    – fdb
    Commented Oct 28, 2015 at 14:25

The problem with @fbd's quotidian is it's often used to mean usual or customary; everyday.

Alternatively, also from Latin (but actually only coined in 1959) there's...

circadian - noting or pertaining to rhythmic biological cycles recurring at approximately 24-hour intervals.

Which adjective to use would depend significantly on the exact context. Quotidian would probably suit your daily office report, but your daily bowel movement fits better with circadian.

  • 2
    And quotidian even is used to mean commonplace, often with a slightly negative tone.
    – bib
    Commented Oct 27, 2015 at 14:59
  • @bib: Yes, that's how I normally understand everyday (i.e. - ordinary). So your everyday clothes are by implication inferior to your Sunday best (which is idiomatically so common we don't usually even bother specifying clothing). Commented Oct 27, 2015 at 16:51

Preface: I only saw that you already knew about 'diurnal' after writing the following. Please tell me if you prefer this answer's deletion.

What about the adjective diurnal (which no other post has suggested, as of the time of this post)? For more on its Latinate etymology, see Etymonline.

More generally, have you read Wikipedia's List of Germanic and Latinate equivalents in English, which was where I first encountered 'diurnal' above as the Latinate synonym for 'daily'?

  • Diurnal is the opposite of nocturnal, so it is more related to sunlight cycle.
    – moonwave99
    Commented Oct 28, 2015 at 11:45
  • "Diurnal tide" refers to the tides of 24-hour period, regardless of what time of the day it's high tide or low tide. Commented Jan 28, 2020 at 1:18

If "Circadian" means approximately daily then logically "dian" should mean daily. While this word is not used according to Google, it is perhaps an idea to create it.

  • We already have that word, and it’s a noun not an adjective. A dian per the OED is ”a trumpet call or drumroll at early morn”. It derives from Romance dia from Latin dies and is of course related to quotidian.
    – tchrist
    Commented Oct 28, 2015 at 10:33

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