Editing Latin grammar (section)

===Declensions===
{{Main|Latin declension}}

====1st and 2nd declensions====
Latin nouns are divided into different groups according to the patterns of their case endings. These different groups are known as ''declensions''. Nouns with ''-a'' in the nominative singular, like {{lang|la|puella}} "girl" are known as ''1st declension nouns'', and so on.

The following table shows the declension of {{lang|la|puella}} "girl" (1st declension), {{lang|la|dominus}} "lord, master" (2nd declension masculine), and {{lang|la|bellum}} "war" (2nd declension neuter):{{sfn|Kennedy|1962|pp=17-19}}

{| class="wikitable sortable"
! rowspan="2" |Case
! colspan="2" |feminine
!
! colspan="2" |masculine
!
! colspan="2" |neuter
!
! rowspan="2" |Br
! rowspan="2" |GL
! rowspan="2" |Wh
|-
! class="unsortable" |''1 sg.''
! class="unsortable" |''1 pl.''
! class="unsortable" |
! class="unsortable" |''2 sg.''
! class="unsortable" |''2 pl.''
! class="unsortable" |
! class="unsortable" |''2n sg.''
! class="unsortable" |''2n pl.''
! class="unsortable" |
|-
| Nominative
| '''{{lang|la|puella|italic=no}}''' || '''{{lang|la|puellae|italic=no}}''' || ||'''{{lang|la|dominus|italic=no}}''' || '''{{lang|la|dominī|italic=no}}''' || ||'''{{lang|la|bellum|italic=no}}''' || '''{{lang|la|bella|italic=no}}''' || ||  1 || 1 || 1
|-
| Vocative
| '''{{lang|la|puella|italic=no}}''' || '''{{lang|la|puellae|italic=no}}''' ||  ||'''{{lang|la|domine|italic=no}}''' || '''{{lang|la|dominī|italic=no}}''' ||  ||'''{{lang|la|bellum|italic=no}}''' || '''{{lang|la|bella|italic=no}}''' ||  || 2 || 5 ||6 
|-
| Accusative
| '''{{lang|la|puellam|italic=no}}''' || '''{{lang|la|puellās|italic=no}}''' || ||'''{{lang|la|dominum|italic=no}}''' || '''{{lang|la|dominōs|italic=no}}''' || ||'''{{lang|la|bellum|italic=no}}''' || '''{{lang|la|bella|italic=no}}''' || || 3 || 4 || 4 
|-
| Genitive
| '''{{lang|la|puellae|italic=no}}''' || '''{{lang|la|puellārum|italic=no}}''' || ||'''{{lang|la|dominī|italic=no}}''' || '''{{lang|la|dominōrum|italic=no}}''' || ||'''{{lang|la|bellī|italic=no}}''' || '''{{lang|la|bellōrum|italic=no}}''' || || 4 || 2 || 2
|-
| Dative
| '''{{lang|la|puellae|italic=no}}''' || '''{{lang|la|puellīs|italic=no}}''' || ||'''{{lang|la|dominō|italic=no}}''' || '''{{lang|la|dominīs|italic=no}}''' || ||'''{{lang|la|bellō|italic=no}}''' || '''{{lang|la|bellīs|italic=no}}''' ||  || 5 || 3 || 3 
|-
| Ablative
| '''{{lang|la|puellā|italic=no}}''' || '''{{lang|la|puellīs|italic=no}}''' || ||'''{{lang|la|dominō|italic=no}}''' || '''{{lang|la|dominīs|italic=no}}''' || ||'''{{lang|la|bellō|italic=no}}''' || '''{{lang|la|bellīs|italic=no}}'''  || || 6 || 6 || 5 
|-
|}

1st declension nouns are usually feminine, except for a few referring to men, such as {{lang|la|agricola}} "farmer" or {{lang|la|poēta}} "poet". The nouns {{lang|la|fīlia}} "daughter" and {{lang|la|dea}} "goddess" have dative and ablative plural {{lang|la|fīliābus, deābus}}. The locative case ends in ''-ae'', pl. ''-īs'', e.g. {{lang|la|Rōmae}} "in Rome", {{lang|la|Athēnīs}} "in Athens".{{sfn|Kennedy|1962|p=17}}

2nd declension nouns in ''-us'' are usually masculine, but those referring to trees (e.g. {{lang|la|pīnus}} "pine tree") and some place names (e.g. {{lang|la|Aegyptus}} "Egypt") are feminine. A few 2nd declension nouns, such as {{lang|la|vir}} "man" and {{lang|la|puer}} "boy", lack endings in the nominative and vocative singular. In the 2nd declension, the genitive plural in some words is optionally ''-um'', especially in poetry:{{sfn|Allen|Greenough|Kittredge|Howard|1903|loc=§49}}{{sfn|Kennedy|1962|p=19}} {{lang|la|deum}} or {{lang|la|deōrum}} "of the gods", {{lang|la|virum}} or {{lang|la|virōrum}} "of men".

Neuter nouns such as {{lang|la|bellum}} "war" have ''-a'' in the nominative plural. In neuter nouns, the vocative and accusative are always the same as the nominative; the genitive, dative, and ablative are the same as the masculine. Most 2nd declension neuter nouns end in ''-um'' but {{lang|la|vīrus}} "poison" and {{lang|la|vulgus}} "crowd" end in ''-us''.

====3rd declension====
Third declension nouns have various patterns of declension. Some decline like the following: {{lang|la|mīles}} "soldier", {{lang|la|urbs}} "city", {{lang|la|corpus}} "body":{{sfn|Kennedy|1962|p=22-26}}

{| class="wikitable sortable" 
! rowspan="2" |Case
! colspan="2" |masculine
!
! colspan="2" |feminine
!
! colspan="2" |neuter
!
! rowspan="2" |Br
! rowspan="2" |GL
! rowspan="2" |Wh
|-
! class="unsortable" |''3 sg.''
! class="unsortable" |''3 pl.''
! class="unsortable" |
! class="unsortable" |''3 sg.''
! class="unsortable" |''3 pl.''
! class="unsortable" |
! class="unsortable" |''3n sg.''
! class="unsortable" |''3n pl.''
! class="unsortable" |
|-
| Nominative
| '''{{lang|la|mīles|italic=no}}''' || '''{{lang|la|mīlitēs|italic=no}}''' ||  ||'''{{lang|la|urbs|italic=no}}''' || '''{{lang|la|urbēs|italic=no}}''' ||  ||'''{{lang|la|corpus|italic=no}}''' || '''{{lang|la|corpora|italic=no}}''' ||  ||   1 || 1 || 1
|-
| Vocative
| '''{{lang|la|mīles|italic=no}}''' || '''{{lang|la|mīlitēs|italic=no}}'''  ||||'''{{lang|la|urbs|italic=no}}''' || '''{{lang|la|urbēs|italic=no}}''' ||  ||'''{{lang|la|corpus|italic=no}}''' || '''{{lang|la|corpora|italic=no}}''' || ||  2 || 5 ||6 
|-
| Accusative
| '''{{lang|la|mīlitem|italic=no}}''' || '''{{lang|la|mīlitēs|italic=no}}'''  ||||'''{{lang|la|urbem|italic=no}}''' || '''{{lang|la|urbēs/-īs|italic=no}}''' ||  ||'''{{lang|la|corpus|italic=no}}''' || '''{{lang|la|corpora|italic=no}}'''  ||||3 || 4 ||4
|-
| Genitive
| '''{{lang|la|mīlitis|italic=no}}''' || '''{{lang|la|mīlitum|italic=no}}'''  ||||'''{{lang|la|urbis|italic=no}}''' || '''{{lang|la|urbium|italic=no}}''' ||  ||'''{{lang|la|corporis|italic=no}}''' || '''{{lang|la|corporum|italic=no}}''' || ||  4 || 2 || 2
|-
| Dative
|'''{{lang|la|mīlitī|italic=no}}''' || '''{{lang|la|mīlitibus|italic=no}}''' || ||'''{{lang|la|urbī|italic=no}}''' || '''{{lang|la|urbibus|italic=no}}''' ||  ||'''{{lang|la|corporī|italic=no}}''' || '''{{lang|la|corporibus|italic=no}}''' || ||  5 || 3 || 3 
|-
| Ablative
|'''{{lang|la|mīlite|italic=no}}''' || '''{{lang|la|mīlitibus|italic=no}}''' || || '''{{lang|la|urbe|italic=no}}''' || '''{{lang|la|urbibus|italic=no}}''' ||  ||'''{{lang|la|corpore|italic=no}}''' || '''{{lang|la|corporibus|italic=no}}''' ||  || 6|| 6 || 5 
|}

There are some variations, however. A few, such as {{lang|la|vīs, vim, vī}} "force", have accusative singular ''-im'' and ablative singular ''-ī''; some, like {{lang|la|ignis}} "fire", optionally have ''-ī'' instead of ''-e'' in the ablative singular. The genitive plural in some nouns is ''-um'', in others ''-ium''. (For details, see [[Latin declension]].) 3rd declension nouns can be of any gender.

It is not usually possible to guess the genitive of a noun from the nominative: {{lang|la|dux}} "leader" has genitive {{lang|la|ducis}} but {{lang|la|rēx}} "king" has {{lang|la|rēgis}}; {{lang|la|pater}} "father" has genitive {{lang|la|patris}} but {{lang|la|iter}} "journey" has {{lang|la|itineris}}. For this reason the genitive is always given in dictionaries, and can be used to deduce the remaining cases.

====4th and 5th declensions====
4th and 5th declension nouns are less common. They decline like the following ({{lang|la|manus}} "hand", {{lang|la|genū}} "knee", {{lang|la|diēs}} "day"):{{sfn|Kennedy|1962|p=30-31}}
 
{| class="wikitable sortable"
! rowspan="2" |Case
! colspan="2" |feminine
!
! colspan="2" |neuter
!
! colspan="2" |
!
! rowspan="2" |Br
! rowspan="2" |GL
! rowspan="2" |Wh
|-
! class="unsortable" |''4 sg.''
! class="unsortable" |''4 pl.''
! class="unsortable" |
! class="unsortable" |''4 sg.''
! class="unsortable" |''4 pl.''
! class="unsortable" |
! class="unsortable" |''5 sg.''
! class="unsortable" |''5 pl.''
! class="unsortable" |
|-
| Nominative
| '''{{lang|la|manus|italic=no}}''' || '''{{lang|la|manūs|italic=no}}''' ||  ||'''{{lang|la|genū|italic=no}}''' || '''{{lang|la|genua|italic=no}}'''||  ||'''{{lang|la|diēs|italic=no}}''' || '''{{lang|la|diēs|italic=no}}''' || ||  1|| 1 ||1 
|-
| Vocative
| '''{{lang|la|manus|italic=no}}''' || '''{{lang|la|manūs|italic=no}}''' ||  ||'''{{lang|la|genū|italic=no}}''' || '''{{lang|la|genua|italic=no}}'''||  ||'''{{lang|la|diēs|italic=no}}''' || '''{{lang|la|diēs|italic=no}}''' || ||  2||5 ||6 
|-
|Accusative
| '''{{lang|la|manum|italic=no}}''' || '''{{lang|la|manūs|italic=no}}''' ||  ||'''{{lang|la|genū|italic=no}}''' || '''{{lang|la|genua|italic=no}}'''||  ||'''{{lang|la|diēm|italic=no}}''' || '''{{lang|la|diēs|italic=no}}''' || ||  3||4 ||4 
|-
| Genitive
| '''{{lang|la|manūs|italic=no}}''' || '''{{lang|la|manuum|italic=no}}''' ||  ||'''{{lang|la|genūs|italic=no}}''' || '''{{lang|la|genuum|italic=no}}'''||  ||'''{{lang|la|diēī|italic=no}}''' || '''{{lang|la|diērum|italic=no}}''' ||  || 4|| 2 ||2 
|-
| Dative
| '''{{lang|la|manuī|italic=no}}''' || '''{{lang|la|manibus|italic=no}}''' ||  ||'''{{lang|la|genuī, genū|italic=no}}''' || '''{{lang|la|genibus|italic=no}}'''||  ||'''{{lang|la|diēī|italic=no}}''' || '''{{lang|la|diēbus|italic=no}}''' ||  || 5|| 3 ||3 
|-
| Ablative
| '''{{lang|la|manū|italic=no}}''' || '''{{lang|la|manibus|italic=no}}''' ||  ||'''{{lang|la|genū|italic=no}}''' || '''{{lang|la|genibus|italic=no}}'''||  ||'''{{lang|la|diē|italic=no}}''' || '''{{lang|la|diēbus|italic=no}}''' ||  || 6|| 6 ||5 
|-
|}

4th declension nouns are usually masculine, but a few, such as {{lang|la|manus}} "hand" and {{lang|la|anus}} "old lady", are feminine. There are only four 4th declension neuter nouns.{{sfn|Allen|Greenough|Kittredge|Howard|1903|loc= §91}}

5th declension nouns (except for {{lang|la|diēs}} (m) "day") are usually feminine. {{lang|la|rēs}} "thing" is similar to {{lang|la|diēs}} except for a short ''e'' in the genitive and dative singular {{lang|la|reī}}.

====Other nouns====
In addition to the above there are some irregularly declined nouns, mostly borrowed from Greek, such as the name {{lang|la|Aenēās}} "Aeneas" (1st declension masculine).{{sfn|Kennedy|1962|p=34-36}}

The vocative is nearly always the same as the nominative, except in 1st and 2nd declension masculine singular words, such as {{lang|la|Aenēā!}} "Aeneas!" and {{lang|la|domine!}} "master!/lord!". Some words, such as {{lang|la|deus}} "god", have no separate vocative, however.