Latin Noun Endings of the Five Declensions
| 1 f/m | 2 m | 2 n | 3 f/m | 3 n | 3-i f/m | 3-i n | 4 m/f | 4 n | 5 f/m | |
|---|---|---|---|---|---|---|---|---|---|---|
| Nom. | -a | -us/-er | -um | --- | --- | --- | --- | -us | -u | -es |
| Gen. | -ae | -i | -i | -is | -is | -is | -is | -us | -us | -ei |
| Dat. | -ae | -o | -o | -i | -i | -i | -i | -ui | -u | -ei |
| Acc. | -am | -um | -um | -em | --- | -em | --- | -um | -u | -em |
| Abl. | -a | -o | -o | -e | -e | -i/-e | -i | -u | -u | -e |
| plural forms | ||||||||||
| Nom. | -ae | -i | -a | -es | -a | -es | -ia | -us | -ua | -es |
| Gen. | -arum | -orum | -orum | -um | -um | -ium | -ium | -uum | -uum | -erum |
| Dat. | -is | -is | -is | -ibus | -ibus | -ibus | -ibus | -ibus | -ibus | -ebus |
| Acc. | -as | -os | -a | -es | -a | -es | -ia | -us | -ua | -es |
| Abl. | -is | -is | -is | -ibus | -ibus | -ibus | -ibus | -ibus | -ibus | -ebus |
Third declension nouns are -i stem if they are feminine or masculine and 1) end in -s or -x and have the same number of syllables in the nominative and genitive singular (they usually have -is in the nominative: e.g. turris, turris, f.), or 2) have double consonants before the genitive ending is added (e.g. linter, lintris, f.). Neuter nouns are 3rd -i stem if their nominative form ends in -al, -ar, or -e.
Vocative forms are usually the same as the nominative, except that -us masculine nouns in the second declension have a vocative singular in -e. If the nominative ends in -ius [e.g. Vergilius] the vocative singular just drops the -us [e.g. Vergili]).