diēs
Back-formed from the accusative diem (at a time when the vowel was still long), from Proto-Italic *djēm, the accusative of *djous, from Proto-Indo-European *dyḗws (“heaven, sky”).[1] The original nominative survives as *diūs in two fossilised phrases: mē diūs fidius (an interjection) and nū diūs tertius (“day before yesterday”, literally “now (is) the third day”). The d in diēs is a puzzle with some suggesting dialect borrowing and others referring to an etymon *diyew- via Lindeman's Law. But note the possible Proto-Italic allophony between *-CjV- and *-CiV-, which may be the cause for this divergence (See WT:AITC).
Cognate with Ancient Greek Ζήν (Zḗn), Old Armenian տիւ (tiw, “daytime”), Old Irish día, Welsh dydd, Polish dzień, but not English day, which is a false cognate. The Italic stem was also the source of Iovis, the genitive of Iuppiter and was generally interchangeable with it in earlier times, still shown by the analogical formation Diēspiter.
- (Classical Latin) IPA(key): /ˈdi.eːs/, [ˈd̪ieːs̠]
- (modern Italianate Ecclesiastical) IPA(key): /ˈdi.es/, [ˈd̪iːes]
diēs m or f (genitive diēī); fifth declension
- A day, particularly:
- A solar or sidereal day of about 24 hours, especially (historical) Roman dates reckoned from one midnight to the next. [ quotations ▼]
- Daytime: a period of light between sunrise and sunset.
- (often in the feminine) A set day: a date, an appointment.
- Dates in the Roman calendar were reckoned according to the calends (kalendae), the nones (nōnae), and the ides (īdūs). The calends of every month was its first day; the nones and ides of most months were their 5th and 13th days; and the nones and ides of the four original 31-day months—Mārtius, Maius, Quīntīlis or Iūlius, and Octōber—were two days later. January 1st was thus kalendae Iānuāriae or Iānuāriī. The day preceding any of these three principal days was called its eve (prīdiē). January 12th was thus prīdiē īdūs Iānuāriās or Iānuāriī (pr. Id. Ian.). All other days of the month were expressed by counting inclusively forward to the next of these three principal days and, in early Latin, this was expressed in the ablative. January 11th was thus diē tertiō ante īdūsIānuāriās or Iānuāriī (III Id. Ian.). By the time of classical Latin, however, the ante had moved to the beginning of the expression and it became an accusative absolute: ante diem tertium īdūsIānuāriās or Iānuāriī (a. d. III Id. Ian.).[2] In this form, the date functioned as a single indeclinable noun and could serve as the object of prepositions such as ex and in.[3]
- Unlike most fifth-declension nouns, diēs is not exclusively feminine. It was typically masculine, particularly in the plural. It appears as a feminine noun when being personified as a goddess, in some specific dates, in reference to the passing of time, and occasionally in other contexts.
Fifth-declension noun.
| Case | Singular | Plural |
|---|---|---|
| Nominative | diēs | diēs |
| Genitive | diēī | diērum |
| Dative | diēī | diēbus |
| Accusative | diem | diēs |
| Ablative | diē | diēbus |
| Vocative | diēs | diēs |
- (antonym(s) of “daytime”): nox