I-Stem Nouns: urbs, civis, mare
I-stems keep an i before some endings.
How It Works
You can often spot an i-stem noun by its shape.
- Nouns in -is with the same number of syllables in the nominative and the genitive: civis, civis; navis, navis.
- Nouns in -s or -x after another consonant: urbs, urbis; nox, noctis; mors, mortis.
- Neuter nouns in -e, -al and -ar: mare, animal.
| Case | Singular | Plural |
|---|---|---|
| nominative | mare | maria |
| genitive | maris | marium |
| dative | mari | maribus |
| accusative | mare | maria |
| ablative | mari | maribus |
These shapes are guides, not laws. Canis (dog) and iuvenis (young man) look like i-stems, but their genitive plurals are canum and iuvenum. Learn the genitive plural with each noun.
Examples (5)
- Apostoli pisces in mari capiunt.
The apostles catch fish in the sea.
Mari is the ablative singular of mare, with -i.
- Multa animalia in silva habitant.
Many animals live in the forest.
Animalia is the plural of animal, with -ia.
- Muri urbium alti sunt.
The walls of the cities are high.
Urbium is the genitive plural of urbs.
- Nautae navium nomina scribunt.
The sailors write the names of the ships.
Navium is the genitive plural of navis.
- Ave maris stella.
Hail, star of the sea.
Maris is the genitive singular of mare. The words are the start of a hymn to Mary.
Common Mistakes
Leaving out the i in the genitive plural of an i-stem.
Voces civum audio.Voces civium audio.Civis is an i-stem noun, so its genitive plural is civium.
Adding only -a to the plural of a neuter i-stem.
Multa animala in silva habitant.Multa animalia in silva habitant.Animal is a neuter i-stem, so its plural ends in -ia: animalia.
How It Connects
Learn This First
I-stem nouns differ from the plain third family in the genitive plural, and the neuter ones in the ablative and the plural.
- Third Declension: Genitive -is, -um, -ium
Know the genitive, because i-stem nouns add -ium in the genitive plural: urbium, civium.
Level 3 - Third Declension: Ablative -e, -ibus
Know the ablative in -e and -ibus, because i-stem neuter nouns have -i there: mari, from mare.
Level 3 - Third Declension Neuter: corpus, nomen
Know third declension neuter nouns, because mare and animal are neuter i-stems with -ia in the plural: maria, animalia.
Level 3
Related Patterns
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Patterns that build on this one.
Words in This Pattern
Practice I-Stem Nouns: urbs, civis, mare in Bubblegum
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