It’s Friday the 13th, so time for another sesquipedalian paraskevidekatriaphobia word post! Despite the date on the post, I actually finished this early, on the nudiustertian morning.
When it comes to single-word expressions, English conceives of time and the relative positions of days in just three categories: yesterday, today, and tomorrow. Other languages have single words for what are in English slightly more complex phrases; Korean has 모레 (rhymes with “moray” in “Moray eel”) and even 글피 (“geul-pi”) for “the day after tomorrow” and “two days after tomorrow,” respectively, and Russian and Swedish have позавчера (pozavchera) and i förrgår for “the day before yesterday.”*
The equivalents in English, on the other hand, are largely forgotten, including this obscure adjective dating back to the 1600s: nudiustertian.
The eagle-eyed among you, knowing that we’re talking about days, might wonder if the “diu” in the middle comes from the same word as “diurnal,” an adjective to describe daytime activities. (Some people tend to keep pretty nocturnal hours, but most humans are by default diurnal.) And you’d be correct! The base form of this word is actually dies, which you might remember from English teachers telling you to carpe diem, or from your requiem masses as Dies Irae.
There are two other bits of Latin in there: nu is from nunc, meaning “now,” though not seen often in English (and not to be confused with nuntiare in Old French, which relates to many speaking verbs: announce, denounce, pronounce, etc.). Ter, on the other hand, turns up in “tertiary” (after primary and secondary comes tertiary) and isn’t too far from the tri- morpheme for three-related words (triple, triangle, triune).
So we can see how the word has the most important bits of the original Latin phrase: nunc dies tertius est, or “now it is the third day.” As in, if the event happened on the first day, then the second day would be yesterday and the third day would be today, so “now it is the third day.”
It’s not hard to imagine why, when English already had the purely Germanic ereyesterday to do the same job. Why use a convoluted Latin mishmash instead of the much more intuitive Germanic option that’s already in use? It’s visually much cleaner and (to my mind) involves a less complicated numerical concept. (If the day before yesterday was two days ago, how can today be the third day?) What’s more puzzling is why ereyesterday hasn’t stuck around, either. Is “the day before yesterday” that much easier to say?
*I want to say that I’ve heard häromdagen much more often than i förrgår, but while the former is more like “the other day,” i förrgår refers specifically to “the day before yesterday.”