Latin declension

Latin noun declension features seven cases:

• nominative (subject)
• genitive (possessive - of which)
• dative (indirect object - to or for which)
• accusative (object)
• ablative (expresses the means or tools by which one accomplishes something)
• vocative (used for addressing another person in direct speech, usually identical to nominative)
• locative (archaic; used to show location in cities, towns, and small islands)

Note: Neuter nouns of all declension classes share two properties:

• The forms for nominative and accusative singular are identical.
• The forms for nominative and accusative plural are identical, and they always end in -a.

Since this behavior tends to obscure the situation, neuter paradigma words were generally avoided (though this isn't always possible).

As in English, there are two numeri (singular and plural). There are five declension classes:

1. a declension

Nouns of this class usually end in -a and are usually of feminine grammatical gender. Example (paradigma is terra - land, earth):

The a declension has no special forms for the vocative; nominative is used instead. The genitive singular originally had the ending -as (preserved in the expression pater familias) and the dative and ablative plural had -abus (preserved in cum dis et deabus).

Greek words ending in -es or -as (like the name Aeneas) are also declined according to this scheme. They, however, do have a vocative form (stem + -a, e.g. Aenea).

2. o declension

Nouns of this class end in -us, -r or -um. Nouns ending in -us and -r are of masculine gender, those ending in -um of neuter gender.

Example I, words ending in -us (paradigma hortus - garden)

Example II, words ending in -um (paradigma verbum - word)

Example III, words ending in -r (paradigma ager - field)

Note that the e in the nominative singular form is just an insertion to ease pronunciation and is omitted in all other forms. There are however some words, where the e belongs to the stem proper and can't be omitted. These are: gener (son-in-law), socer (father-in-law), puer (boy), vesper (evening) and liberi (children - only occurs in plural forms).

Greek words ending in -eus are declined like regular nouns ending in -us, with the single exception that the vocative singular is formed by appending -u to the "stem" (as in Orpheus - Orpheu)

3. mixed declension

Nouns of this class are divided into two subcategories according to the ending of their stems.

3.1 consonantal stems

This class comprises nouns whose stem ends in a consonant. Some nouns of this class don't have a particular ending for nominative singular. Of these, some use the raw stem instead (as with sol - sun), and some have a special contracted form (like natio - people, tribe). Finally, some consonantal nouns have the nominative singular ending "-s" (like rex - king, which originally was regs). Examples:

3.2: short -i stems

This class consists of nouns whose stem ends in a short -i. According to their nominative form, one can subdivide them into three groups: Some nouns (like nubes - cloud) have nominative forms consisting of the same number of syllables as the other forms, some have shortened nominative forms (like ars - art) and some have non-standard nominative forms ending in -e, -al or -ar (like animal - animal). Examples:

A small group of nouns has a declension scheme especially rich in "i"s. They are: febris - fever, puppis - quarterdeck, securis - axe, sitis - thirst, turris - tower, tussis - cough and vis - power. Example:

4. u declension

Nouns of this class end in -us or -u. The former ones usually are of masculine gender, the latter ones are always neuter.

Example I, nouns ending in -us (paradigma lacus - lake)

Originally, dative and ablative plural ended in -ubus.

Example II, nouns ending in -u (paradigma cornu - horn)

5. e declension

Nouns of this class end in -es. Nearly all of them are of feminine grammatical gender. Example (paradigma dies - day):