What are declensions?
Declensions are modifications of nouns to match them to the case in which they are being used. For example, in English, we have he/him; him is in the accusative case as it is used as a direct object. In Latin, this could be amica/amicam.
What are cases?
Cases are the different roles a noun can take in a sentence. In Latin, there are 7 cases, 6 of note. -Nominative: subject -Genitive: possession (‘s, of) -Dative: indirect object (to, for) -Accusative: direct object -Ablative: adverbial clauses (with, by, from, in) -Vocative: imperative/talking to someone
First Declension
The first declension applies to first declension nouns (duh), most of which are feminine (puella, pecunia); however, some first declension nouns are male, generally those associated with male occupations such as poeta, nauta, and agricola. We determine the base of a noun by dropping its genitive ending. We determine the base of a adj. by dropping its feminine ending.
| Singular | Plural | |
|---|---|---|
| Nom. | -a | -ae |
| Gen. | -ae | -arum |
| Dat. | -ae | -is |
| Acc. | -am | -as |
| Abl. | -a | -is |
| Voc. | -a | -ae |
| Singular | Plural | |
|---|---|---|
| Nom. | porta | portae |
| Gen. | portae | portarum |
| Dat. | portae | portis |
| Acc. | portam | portas |
| Abl. | porta | portis |
| Voc. | porta | portae |
Second Declension
Second declension nouns tend to be masculine, (or neuter, but this different ending), ending in -us or rarely -er. Again, like the first declension, take the genitive, drop the ending, and decline the base.
| Singular | Plural | |
|---|---|---|
| Nom. | -us | -ī |
| Gen. | -ī | -orum |
| Dat. | -ō | -is |
| Acc. | -um | -os |
| Abl. | -ō | -is |
| Voc. | -e | -ī |
| Singular | Plural | |
|---|---|---|
| Nom. | magnus | amicī |
| Gen. | magnī | amicorum |
| Dat. | magnō | amicīs |
| Acc. | magnum | amicos |
| Abl. | magnō | amicīs |
| Voc. | magnē | amicī |
| Some second declension nouns, as mentioned above, end with -er. For some of these, they keep the e, like puer, but others like ager do not. That’s why we rely on the genitive. |
| Singular | Plural | |
|---|---|---|
| Nom. | puer | puerī |
| Gen. | puerī | puerorum |
| Dat. | puerō | pueris |
| Acc. | puerum | pueros |
| Abl. | puerō | pueris |
| Voc. | puer | puerī |
| Singular | Plural | ||
|---|---|---|---|
| Nom. | ager | agrī | |
| Gen. | agrī | agrorum | |
| Dat. | agrō | agrīs | |
| Acc. | agrum | agrōs | |
| Abl. | agrō | agrīs | |
| Voc. | ager | agrī |
Second Declension Neuter
There are many nouns in the second declension which are neuter (no gender). They will end with -um in the Nominative Singular. They decline slightly differently than masculine second Declension nouns.
| Singular | Plural | |
|---|---|---|
| Nom. | -um | -a |
| Gen. | -ī | -orum |
| Dat. | -ō | -is |
| Acc. | -um | -a |
| Abl. | -ō | -is |
| Singular | Plural | |
|---|---|---|
| Nom. | donum | dona |
| Gen. | donī | donorum |
| Dat. | donō | donīs |
| Acc. | donum | dona |
| Abl. | donō | donīs |
Third Declension
The third declensions contains nouns of all three genders. These nouns tend to have a large variety of nominative singular endings. Thankfully, they all share the same genitive singular ending -is. The vocative is the same as the nominative.
Male and Female nouns, end with -em in the accusative singular and with an -ēs for the nominative and accusative plural. For neuters, the accusative singular is the same as the nominative singular and the nominative and accusative plural end with -a instead of -ēs.
Male/Female
| Singular | Plural | |
|---|---|---|
| Nom. | — | -ēs |
| Gen. | -is | -um |
| Dat. | -ī | -ibus |
| Acc. | -em | -ēs |
| Abl. | -e | -ibus |
| Neuter |
| Singular | Plural | |
|---|---|---|
| Nom. | — | -a |
| Gen. | -is | -um |
| Dat. | -ī | -ibus |
| Acc. | — | -a |
| Abl. | -e | -ibus |
| Singular | Plural | |
|---|---|---|
| Nom. | rex | regēs |
| Gen. | regis | regum |
| Dat. | regī | regibus |
| Acc. | regem | regēs |
| Abl. | rege | regibus |
| Singular | Plural | |
|---|---|---|
| Nom. | virtūs | virtutēs |
| Gen. | virtutis | vertutum |
| Dat. | vertutī | vertutibus |
| Acc. | vertutem | virtutēs |
| Abl. | virtute | virtutibus |
| Singular | Plural | |
|---|---|---|
| Nom. | homo | hominēs |
| Gen. | hominis | hominum |
| Dat. | hominī | hominibus |
| Acc. | hominem | hominēs |
| Abl. | homine | hominibus |
Third Declension i-Stem Nouns
There are some fun third declension nouns who have a characteristic i in certain case endings. We, therefore, call these nouns, i-Stem nouns. For masculine/feminine nouns, the only difference is that the genitive is now -ium instead of -um. For neuter, i-stem nouns, the plural nominative, accusative, and vocative are now -ia instead of -a. In addition, the ablative is now -ī. This one is generally pretty easy to natural intuit since animala sounds weird, but animalia does not. Finally, there is the word vīs (meaning strength or force) which has its own set of declensions, which is great. They are listed below, and the irregular cases are bolded. Note: there is an alternate spelling of the i-stem noun cīvēs (citizen plural) as cīvīs.
| Singular | Plural | |
|---|---|---|
| Nom. | vīs | vīrēs |
| Gen. | vīs | vīrium |
| Dat. | vī | vīribus |
| Acc. | vim | vīrēs |
| Abl. | vī | vīribus |
How to tell if a noun is an i-stem noun?
If the noun is gendered and has the same number of syllables in the nominative and genitive, it is parisyllabic and an i-stem. Examples: hostis, hostis , nāvis, nāvis, mōlēs, mōlis.
If the noun is gendered and ends with two consonants. Example: ars, artis, dēns, detis, nox, noctis.
If the noun is neutered and ends with -al, -ar, or -e. It is an i-stem noun. Examples: animal, animālis, exemplar, exemplāris, mare, maris.
Third Declension Adjectives
We have already seen many adjectives of the first major group (where the adjectives are of the first/second declension). The second main group is declined like i-stem third declension nouns, except the ablative singular of all genders ends with -ī, not just the neuter. There are three styles of i-stem adjectives. Ones where each the masculine, feminine, and neuter have unique nominative singular forms, ones where the masculine and feminine have one nominative singular form while the neuter has another form, and one where the masculine, feminine, and neuter are all of the same form.
Adjective of Three Endings ācer, ācris, ācre
| Gender | Masculine & Feminine | Neuter | ||
|---|---|---|---|---|
| Number | Singular | Plural | Singular | Plural |
| Nominative | ācer, ācris | ācrēs | ācre | ācria |
| Genitive | ācris | ācrium | ācris | ācrium |
| Dative | ācrī | ācribus | ācrī | ācribus |
| Accusative | ācrem | ācres | ācre | ācria |
| Ablative | ācrī | ācribus | ācrī | ācribus |
Special -ius adjectives
These are special adjectives who belong to the first/second declension but have the genitive singular ending -īus and the dative singular ending -ī. Some example words are: sōlus, -a, -um: alone, only alius, alia, aliud: another other
Fourth Declension
Tired of declensions? Well, there are still more to go, so y’know. The fourth declension, thankfully, is rather small, easy to identify, and has rather simple endings. Fourth declension nouns are generally masculine, with the nominative singular ending -us, and neuters with the nominative singular ending -ū. In either case, the fourth declension nouns end with -ūs in the genitive singular.
Note that it is important to identify a noun’s declension from its genitive singular form since there are third and second declension nouns which end with -us as well in the nominative.
Masculine and Feminine Endings
| Singular | Plural | |
|---|---|---|
| Nominative | frūctus | frūctūs |
| Genitive | frūctūs | frūctuum |
| Dative | frūctuī | frūctibus |
| Accusative | frūctum | frūctūs |
| Ablative | frūctū | frūctibus |
| Neuter Endings |
| Singular | Plural | |
|---|---|---|
| Nominative | cornū | cornua |
| Genitive | cornūs | cornuum |
| Dative | cornū | cornibus |
| Accusative | cornū | cornua |
| Ablative | cornū | cornibus |