What is the best translation for the attributive "one-day" (i.e. "that lasts one day)? For example, consider:

one-day tour
one-day conference

How about "two-day", "one-month", "one-year", etc.? There are particular adjectives like "biennial" "triennial" in English, so I wonder if something like these also exists in Latin.

3 Answers 3


I'd say simply unius diei, "of one day". It's not an adjective, but nothing says that the idiomatic solution should be an adjective.

The phrase is well attested, and at least some of the attestations are relevant.

The phrase is also easily generalized to any situation ("of six years") without the trouble of deriving new words that may or may not have a prior existence. In some cases there are nice adjectives (from which many familiar English ones derive), but I will leave them out of this answer and only focus on the simplest solution.


I second Joonas' answer. I would also just like to point out that "lasting of one day" seems to be the original meaning of diurnus, and is still found in that sense in Ovid's Heroides 6.37, as Lewis and Short mention:

    et subito natos arma tulisse viros,
terrigenas populos civili Marte peremptos
    inplesse aetatis fata diurna suae.

and the sudden warriors bearing arms,
an earthborn people killed in civil war
fulfilling their life’s destiny in a day. (Trans. Klein)

However, the normal way it's used is "only occurring during the day", without a sense of duration of how many days. Therefore I would only suggest it in rare cases in poetry, but not your typical language on conference signs.

As far as words with -ennial, you might find this question relevant. Interestingly, I also noticed there's dieteris ("a period of two-years"), from the Greek διετηρίς (the noun form of the adjective διετής, from δι- "two" and ἔτος "year").


There is a sequence of adjectives ending in -duānus, but there doesn't seem to be one for "one day":

These are derived from the nouns bīduum ("two-day period"), trīduum, etc.

Also—if this matters to you—they do not seem to be Classical words. (I only found one use in the PHI corpus: "triduani spectaculi" in Apuleius Metamorphoses 10.18.9.)

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