Latin Nouns — All 5 Declensions Explained
Declining Latin nouns is one of the first major hurdles in Latin class. Five declension classes, six cases, three genders—it sounds like a lot. However, the system behind it is completely logical.
In this article, you’ll learn: what declension means in Latin, how to identify each declension class by its genitive singular, all five tables with key endings—and how to practice directly with the Lapicida Noun Module. This article is part of Lapicida’s “Learning Latin” section.
What is the declension of Latin nouns?
The declension of Latin nouns is the adaptation of the word ending to case and number (singular/plural). There are 5 declension classes and 6 cases. You can identify which class a noun belongs to by its genitive singular form—it always appears in the dictionary immediately after the nominative.
| Declension | Genitive Sing. | Gender | Example |
|---|---|---|---|
| 1st Declension (a-declension) | -ae | usually feminine | puella, -ae (girl) |
| 2nd declension (o-declension) | -i | masc./neut. | servus, -i (slave) / templum, -i (temple) |
| 3rd declension (consonantal + i) | -is | masc./fem./neut. | rex, regis (king) |
| 4th declension (u-declension) | -us | masc./neut. | manus, -us (hand) |
| 5th declension (e-declension) | -ei | usually fem. | res, rei (thing) |
Basic rule: Determine the genitive singular → Identify the declension class → Add the endings.
More blog posts on this topic:
Declining Latin Nouns — in 3 Steps
Step 1: Determine the genitive singular
The dictionary always lists: Nominative Sing., Genitive Sing. — e.g., rex, regis. The genitive singular reveals the declension class: -ae = 1st decl., -i = 2nd decl., -is = 3rd decl., -us = 4th decl., -ei = 5th decl.
Step 2: Form the stem
Remove the genitive ending from the genitive singular—that is the stem. Example: regis minus -is = stem reg-. Then, all case endings are attached to the stem.
Step 3: Add endings
Add the ending corresponding to the declension class, case, and number. Example: reg- + accusative singular –em = regem. In the 1st, 2nd, 4th, and 5th declensions, the stem can be derived directly from the nominative.
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All 5 declensions — tables with examples
1st Declension — a-Declension (puella) | Genitive Singular: -ae | Gender: mostly feminine
| Case | Singular | Plural |
|---|---|---|
| Nom. | puella | puellae |
| Gen. | puellae | puellarum |
| Dat. | puellae | puellis |
| Acc. | puellam | puellas |
| Abl. | puella | puellis |
More examples: aqua (water), terra (earth), via (road), vita (life)
2nd Declension — o-Declension (servus / templum) | Genitive Singular: -i | Gender: masculine and neuter
| Case | servus (masc.) sing. | servus Pl. | templum (neut.) Sing. | templum Pl. |
|---|---|---|---|---|
| Nominative | servus | servi | templum | templa |
| Gen. | servi | servorum | templi | templorum |
| Dat. | servo | servis | templo | templis |
| Acc. | servum | servos | templum | templa |
| Abl. | servo | servis | templo | templis |
3rd declension (rex, regis) | Genitive singular: -is | Gender: masc./fem./neut. | Derive the stem from the genitive singular!
| Case | rex (masc.) sing. | rex Pl. |
|---|---|---|
| Nominative | rex | reges |
| Gen. | regis | regum |
| Dat. | regi | regibus |
| Acc. | regem | reges |
| Abl. | rege | regibus |
More examples of the 3rd declension: consul, consulis (consul); corpus, corporis (body); civis, civis (citizen); mare, maris (sea)
4th Declension (manus, -us) | Genitive Sing.: -us | Gender: mostly masculine | Important: Gen. Sing. and Nom. Pl. = -us (Caution!)
5th Declension (res, rei) | Genitive Singular: -ei | Gender: mostly feminine | Common examples: res (thing), dies (day/masculine), spes (hope), fides (faith). Learn more about verbs and sentence elements in the “Learning Latin” section.
The 6 Cases — Functions at a Glance
Each case has a clear function in the sentence. This table shows question words and typical usage.
| Case | Interrogative Word | Function | Example |
|---|---|---|---|
| Nominative | Who/What? | Subject | puella scribit — the girl is writing |
| Genitive | Whose? | Possession, genitive object | liber puellae — the girl’s book |
| Dative | To whom? | Indirect object | dat puellae — he gives to the girl |
| Accusative | Whom/What? | Direct object, direction | videt puellam — he sees the girl |
| Ablative | With what/where/from what? | Adverbial, abl. abs. | cum puella — with the girl |
| Vocative | (Form of address) | Direct address | puella! — O girl! |
Common Mistakes When Declining Latin Nouns
- Failure to look up the genitive singular: Without the genitive singular, the declension class is unknown. Always learn all dictionary forms: nom. sing., gen. sing., gen.
- 3rd Declension: Forgetting the stem: rex → the stem is not rex- but reg- (from regis). Nominal forms: regem, reges — not rexem.
- Confusing the 4th Declension Nominative Plural with the Genitive Singular: For *manus*, both the genitive singular and the nominative plural are *manus*. Context determines the form.
- Ignoring gender: Gender helps determine the declension class. dies (masculine!) = 5th declension; puer (masculine, 2nd declension) has a special form: no omission of the -e- in the stem.
Practice Latin Nouns — 4 Exercises
Identify the declension class, case, and number. Then form the required case.
Exercise 1: Which declension does consul, consulis (m.) belong to? Form the accusative singular.
Solution: 3rd declension (genitive singular ending in -is). Stem: consul- → accusative singular: consulem.
Exercise 2: Form the genitive plural of *puella, -ae*.
Solution: 1st declension. Stem: puell-. Genitive plural: puellarum.
Exercise 3: What case and number does “regibus” have?
Solution: Stem: reg- (rex, regis, 3rd declension). Ending -ibus = dative or ablative plural. Exact case to be determined from the context.
Exercise 4: Form the nominative plural of *templum, -i* (neuter, 2nd declension).
Solution: Neuter rule: Nom./Acc. plural = -a. Stem: templ- → Nom. pl.: templa.
Practice Latin Nouns — with Active Recall
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Frequently Asked Questions About Nouns in Latin
How many declensions are there in Latin?
There are 5 declension classes in Latin. They are distinguished by the ending of the genitive singular: 1st decl. (-ae), 2nd decl. (-i), 3rd decl. (-is), 4th declension (-us), 5th declension (-ei). The 3rd declension includes the consonantal and i-declension as subgroups.
How can I tell which declension a Latin noun belongs to?
By its genitive singular form—it always appears in the dictionary immediately after the nominative (e.g., puella, -ae). The genitive ending indicates the declension class: -ae = 1st, -i = 2nd, -is = 3rd, -us = 4th, -ei = 5th declension.
What are the 6 cases in Latin?
Nominative (subject), genitive (possession), dative (indirect object), accusative (direct object / direction), ablative (adverbial phrases, separation, means), vocative (direct address). The vocative is usually identical to the nominative.
What is the difference between the 3rd declension and the consonantal declension?
The 3rd declension includes both the pure consonantal declension and the i-declension. In the i-declension, an “i-” appears in certain forms (e.g., genitive plural -ium instead of -um). Which group applies depends on the ending of the stem.
Why do I have to memorize the genitive singular?
In the 3rd declension, the nominative singular often differs significantly from the stem (rex → stem reg-). Without the genitive singular, you cannot form all case forms correctly. Therefore, always learn the nominative singular and genitive singular together.
