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diēs, rēs: the fifth declension and the ablative of time

The last declension, and how Latin says "on that day" and "in summer" with no preposition.

LatinIntermediate Latin · The fourth and fifth declensionsAbout 3 min: 1 reading, 2 practiceUpdated

After this lesson you can
  • Decline diēs and rēs
  • Know the gender of fifth-declension nouns
  • Use the ablative for time when or within which
Latin Level 2: verbs and the other declensions: lesson 26 of 35
  1. Intermediate Latin · Verbs: the present system
  2. sum: I am, I was, I shall be 3 min
  3. The present of amō and moneō 4 min
  4. The imperfect: was doing 4 min
  5. The future: will do 3 min
  6. The dative with adjectives 3 min
  7. The present of regō and audiō 4 min
  8. The imperfect of regō and audiō, and verbs that take the dative 3 min
  9. The future of regō and audiō 3 min
  10. capiō, and giving orders 3 min
  11. Intermediate Latin · The passive voice
  12. The passive: being done to 3 min
  13. The passive of regō, audiō and capiō; passive infinitives 3 min
  14. Synopses, and the ablative of "from" 3 min
  15. Intermediate Latin · The perfect tenses
  16. fuī, fueram, fuerō: the perfect tenses of sum 3 min
  17. The perfect active: did, have done 5 min
  18. Had done, will have done: pluperfect and future perfect active 3 min
  19. amātus sum: the perfect passive 4 min
  20. Principal parts, prepositions, and yes-or-no questions 5 min
  21. possum, "I can", and the infinitive 3 min
  22. Intermediate Latin · Pronouns
  23. quī, quae, quod: who, which, that 4 min
  24. Intermediate Latin · The third declension
  25. rēx, rēgis: the third declension 4 min
  26. hostis, urbs, mare: i-stems 4 min
  27. vīs and iter; gender in the third declension 4 min
  28. omnis, ācer, pār: third-declension adjectives 3 min
  29. Intermediate Latin · The fourth and fifth declensions
  30. manus, cornū: the fourth declension 3 min
  31. Rōmae, domī, Athēnīs: place and the locative 4 min
  32. diēs, rēs: the fifth declension and the ablative of time 3 min
  33. Intermediate Latin · Pronouns
  34. ego, tū, sē: personal and reflexive pronouns 4 min
  35. ipse, "himself", and īdem, "the same" 3 min
  36. hic, iste, ille: this and that 4 min
  37. aliquis, quīdam, quisque: someone, a certain, each 3 min
  38. Intermediate Latin · Comparison
  39. clārior, clārissimus: comparing adjectives 4 min
  40. melior, optimus: irregular comparison, plūs, and "by how much" 3 min
  41. clārē, fortiter: adverbs and their comparison 4 min
  42. Intermediate Latin · Numerals
  43. ūnus, duo, trēs: numerals, "of" the whole, and "for how long" 5 min
  44. Intermediate Latin · Deponent verbs
  45. hortor, sequor: deponent verbs 3 min

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Pairs with D'Ooge, Latin for Beginners (Ginn, 1909), Lesson XLVIII ("The Fifth or Ē-Declension · The Ablative of Time"), §§ 272–275

What it is

The fifth declension is small: nouns in -ēs, genitive -ēī or -eī.

Casediēs, m., dayrēs, f., thing
Nom.diēsrēs
Gen.diēīreī
Dat.diēīreī
Acc.diemrem
Abl.diērē
Nom. pl.diēsrēs
Gen. pl.diērumrērum
Dat./Abl. pl.diēbusrēbus

The e is long except before -m (diem) and in -eī after a consonant (reī). Fifth-declension nouns are feminine, except diēs and merīdiēs (midday), which are usually masculine. Only diēs and rēs are complete in the plural.

The ablative of time. "When" or "within which" something happens is the ablative with no preposition:

  • prīmā hōrā → at the first hour
  • eō diē → on that day
  • aestāte → in summer
  • paucīs diēbus → within a few days

Quick check

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  1. "on the first day"

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    prīmō diē. Ablative of time when.

Why it matters

Rēs is one of the most useful words in Latin: rēs pūblica (the state, "the public thing"), rēs gestae (deeds), rēs adversae (bad times). And every story needs "on that day" and "in winter".

Worked example

  • Eō diē lēgātus vēnit. → On that day the lieutenant came.
  • Hieme agricolae nōn arant. → In winter the farmers do not plough.
  • Mīlitēs prīmā lūce vēnērunt. → The soldiers came at first light (daybreak).

Common mistake

Adding in for time: wrong: in eō diē. The usual Latin is plain eō diē. (D'Ooge notes in is found occasionally, like English "on the next day" beside "next day".)

Key terms

diēs, diēī, m.
day
rēs, reī, f.
thing, matter
hōra, -ae, f.
hour
annus, -ī, m.
year
aestās, aestātis, f.
summer
hiems, hiemis, f.
winter
lūx, lūcis, f.
light; prīma lūx, daybreak
prīmus, -a, -um
first

Practise the key terms

Tap a card to turn it over. 8 cards.

FrontBack
diēs, diēī, m.day
rēs, reī, f.thing, matter
hōra, -ae, f.hour
annus, -ī, m.year
aestās, aestātis, f.summer
hiems, hiemis, f.winter
lūx, lūcis, f.light; prīma lūx, daybreak
prīmus, -a, -umfirst

Practice

Recognition drill

Pick the right answer, as fast as you can.

All pairs

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FrontBack
genitive singular of rēsreī
accusative singular of diēsdiem
ablative plural of rēsrēbus
genitive plural of diēsdiērum
ablative singular of rēsrē

Quick quiz

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  1. "in summer"

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    aestāte. Ablative of time.

  2. Gender of rēs

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    feminine. Fifth-declension nouns are feminine, except diēs and merīdiēs.

Practise speaking

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You are a patient Latin tutor. Use the classical pronunciation only, never the Church one: c is always k, g is always hard, v sounds like w, ae like the ai in aisle, and long vowels are held longer. Speak slowly. Use only these Latin words: diēs, rēs, hōra, annus, aestās, hiems, lūx, prīmus, eō, vēnit, arant. Say English time phrases like 'on the first day', 'in winter', 'at the first hour' or 'at daybreak', and I will say them in Latin with the ablative and no preposition. Then ask me forms of diēs and rēs. Do 10 rounds. After each answer, tell me what kind of mistake I made, if any, and let me try again, then tell me one thing to improve. Keep every reply under 2 sentences. If I need a name or a town, I will make one up. Speak English except for the Latin itself.

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Good to know. AI feedback on pronunciation is hit and miss, so check yourself against native recordings. This course teaches the classical pronunciation (see lesson 1); AI voices may mix it with the Church (Italian-style) one, so ask for classical and check against lesson 1. Don't share personal details: use a made-up name and town.

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In short

  • Fifth declension: -ēs, -ēī/-eī, -ēī/-eī, -em, -ē; -ēs, -ērum, -ēbus, -ēs, -ēbus.
  • Feminine, except diēs and merīdiēs (usually masculine).
  • Time when or within which: ablative, no preposition.

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Check yourself

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  1. Give the dative singular of rēs.

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    reī.

  2. Translate Prīmā hōrā vēnērunt.

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    They came at the first hour.

  3. Why is there no in in eō diē?

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    Time when is the plain ablative.

Further reading

  • D'Ooge, Latin for Beginners, Lesson XLVIII, §§ 272–275. Public domain; Project Gutenberg.