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hostis, urbs, mare: i-stems

Third-declension nouns with -ium in the genitive plural, and neuters with -ī and -ia.

LatinIntermediate Latin · The third declensionAbout 4 min: 2 reading, 2 practiceUpdated

After this lesson you can
  • Recognise an i-stem noun from its nominative and genitive
  • Use -ium in the genitive plural
  • Decline neuter i-stems with -ī, -ia and -ium
Latin Level 2: verbs and the other declensions: lesson 21 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

Try first

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Pairs with D'Ooge, Latin for Beginners (Ginn, 1909), Lesson XLIII ("The Third Declension · I-Stems"), §§ 241–244

What it is

Some third-declension nouns have an extra i in their stem. It shows up in a few endings, mostly the genitive plural -ium.

Which nouns are i-stems?

  1. Masculine and feminine nouns in -ēs or -is with the same number of syllables in the nominative and genitive: hostis, hostis (enemy), caedēs, caedis (slaughter). Compare mīles, mīlitis: one syllable more, so not an i-stem.
  2. Nouns in -ns and -rs: cliēns, clientis (dependant), pars, partis (part).
  3. One-syllable nouns in -s or -x after a consonant: urbs, urbis (city). Also nox, noctis (night), whose base noct- ends in two consonants.
  4. Neuters in -e, -al, -ar: mare (sea), animal (animal).
Casehostis (m.)mare (n.)
Nom.hostismare
Gen.hostismaris
Dat.hostīmarī
Acc.hostemmare
Abl.hostemarī
Nom. pl.hostēsmaria
Gen. pl.hostium—
Acc. pl.hostīs, hostēsmaria

(Dative and ablative plural: hostibus, maribus. Mare has no genitive plural in use; animal gives animālium.)

Neuter i-stems have -ī in the ablative singular and an i in every plural form: animālī, animālia, animālium.

Quick check

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  1. Genitive plural of urbs, urbis

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    urbium. i-stems have -ium in the genitive plural.

Why it matters

Hostis (an enemy in war), urbs, nāvis (ship), cīvis (citizen), mare and pars are everywhere in Roman history. And hostium or cīvium in a sentence is the clue that a noun is an i-stem.

Worked example

  • Mīlitēs urbem hostium oppugnant. → The soldiers attack the city of the enemy.
  • Nāvēs in marī sunt. → The ships are on the sea.
  • Cīvēs rēgem nōn amant. → The citizens do not love the king.

Common mistake

Treating every -is noun as an i-stem. Hostis, hostis is (same syllables), but mīles, mīlitis and lapis, lapidis are not: their genitives are longer, so they have mīlitum and lapidum.

Key terms

hostis, hostis (-ium), m.
enemy (in war)
urbs, urbis (-ium), f.
city
cīvis, cīvis (-ium), m. and f.
citizen
nāvis, nāvis (-ium), f.
ship
mare, maris (-ium), n.
sea
animal, animālis (-ium), n.
animal
i-stem
a third-declension noun with -ium in the genitive plural

Practise the key terms

Tap a card to turn it over. 7 cards.

FrontBack
hostis, hostis (-ium), m.enemy (in war)
urbs, urbis (-ium), f.city
cīvis, cīvis (-ium), m. and f.citizen
nāvis, nāvis (-ium), f.ship
mare, maris (-ium), n.sea
animal, animālis (-ium), n.animal
i-stema third-declension noun with -ium in the genitive plural

Practice

Sort it

i-stem or consonant stem?

  1. hostis, hostis

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    i-stem. -is with the same syllables: hostium.

  2. mīles, mīlitis

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    Consonant stem. The genitive is longer: mīlitum.

  3. urbs, urbis

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    i-stem. One syllable, -s after a consonant: urbium.

  4. rēx, rēgis

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    Consonant stem. x after a vowel: rēgum.

  5. mare, maris

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    i-stem. Neuter in -e: maria.

  6. legiō, legiōnis

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    Consonant stem. Nominative in -ō: legiōnum.

Quick quiz

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  1. Ablative singular of animal

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    animālī. Neuters in -e, -al, -ar: ablative -ī.

  2. Genitive plural of mīles

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    mīlitum. The genitive has one syllable more, so not an i-stem.

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: hostis, urbs, cīvis, nāvis, mare, animal, mīles, rēx, in. Say one of these nouns (except mare, which has no genitive plural in use) and I will say its genitive plural aloud and tell you whether it is an i-stem. Then give me phrases like 'of the cities' or 'on the sea' for me to say in Latin. 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

  • i-stems: -ēs/-is nouns with equal syllables; -ns, -rs; one-syllable -s/-x after a consonant; neuters in -e, -al, -ar.
  • Masc./fem.: genitive plural -ium; accusative plural -īs or -ēs.
  • Neuters: ablative -ī; plural -ia, -ium.

Mastery check

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Check yourself

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  1. Is nox, noctis an i-stem?

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    Yes: one syllable, and the base noct- ends in two consonants, so noctium.

  2. Give the nominative plural of mare.

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    maria.

  3. Translate Hostēs urbem oppugnant.

    Show answer

    The enemy attack the city.

Further reading

  • D'Ooge, Latin for Beginners, Lesson XLIII, §§ 241–244. Public domain; Project Gutenberg.