Latin grammar

is a heavily inflected language with largely free word order. Nouns are inflected for number and case; pronouns and adjectives are inflected for number, case, and gender; and verbs are inflected for person, number, tense, aspect, voice, and mood. The inflections are often changes in the ending of a word, but can be more complicated, especially with verbs.
Thus verbs can take any of over 100 different endings to express different meanings, for example regō "I rule", regor "I am ruled", regere "to rule", regī "to be ruled". Most verbal forms consist of a single word, but some tenses are formed from part of the verb sum "I am" added to a participle; for example, ductus sum "I was led" or ductūrus est "he is going to lead".
Nouns belong to one of three grammatical genders. The gender of the noun is shown by the last syllables of the adjectives, numbers and pronouns that refer to it: e.g. hic vir "this man", haec fēmina "this woman", hoc bellum "this war". There are also two numbers: singular and plural.
As well as having gender and number, nouns, adjectives, and pronouns have different endings according to their function in the sentence, for example, rēx "the king", but rēgem "the king". These different endings are called "cases". Most nouns have five cases: nominative, accusative, genitive, dative, and ablative. Nouns for people have the vocative. Some nouns for places have a seventh case, the locative; this is mostly found with the names of towns and cities, e.g. Rōmae "in Rome". Adjectives must agree with their nouns in gender, number, and case.
When a noun or pronoun is used with a preposition, the noun must be in either the accusative or the ablative case, depending on the preposition. Thus ad "to, near" is always followed by an accusative case, but ex "from, out of" is always followed by an ablative. The preposition in is followed by the ablative when it means "in, on", but by the accusative when it means "into, onto".
There is no definite or indefinite article in Latin, so that rēx can mean "king", "a king", or "the king" according to context.
File:Priscianus della Robbia OPA Florence.jpg|thumb|300px|Priscian, or the Grammar, marble cameo panel dated 1437–1439 from the bell tower of Florence, Italy, by Luca della Robbia. The scene is an allegory of grammar and, by implication, all of education. Note the opening door in the background and the unshod feet of the first pupil.
Latin word order tends to be subject–object–verb; however, other word orders are common. Different word orders are used to express different shades of emphasis.
An adjective can come either before or after a noun, e.g. vir bonus or bonus vir "a good man", although some kinds of adjectives, such as adjectives of nationality usually follow the noun.
Latin is a pro-drop language; that is, pronouns in the subject are usually omitted except for emphasis, so for example amās by itself means "you love" without the need to add the pronoun tū "you". Latin also exhibits verb framing in which the path of motion is encoded into the verb rather than shown by a separate word or phrase. For example, the Latin verb exit means "he/she/it goes out".
In this article a line over a vowel indicates that it is long.

Nouns

Number

Most Latin nouns have two numbers, singular and plural: rēx "king", rēgēs "kings". A few nouns, called plūrālia tantum, although plural in form, have a singular meaning, e.g. castra "a camp", litterae "a letter", nūptiae "a wedding".

Gender

Nouns are divided into three genders, known as masculine, feminine, and neuter. The difference is shown in the pronouns and adjectives that refer to them, for example:

ipse rēx "the king himself"
ipsa rēgīna "the queen herself"
ipsum bellum "the war itself"

To a certain extent, the genders follow the meanings of the words :

Masculine nouns include all those referring to males, such as dominus "master", puer "boy", deus "god", but also some inanimate objects such as hortus "garden", exercitus "army", mōs "custom". Words in the 2nd declension ending in -us or -er are usually masculine.
Feminine nouns include all those referring to females, such as puella "girl", mulier "woman", dea "goddess", but also inanimate or abstract nouns such as arbor "tree", urbs "city", hūmānitās "kindness", nātiō "nation". Words in the 1st declension like puella ending in -a are usually feminine, with a few exceptions such as poēta "poet". Also feminine are 3rd declension nouns ending in -tās and -tiō.
Neuter nouns all refer to things, such as nōmen "name", corpus "body", bellum "war", venēnum "poison".

Neuter nouns differ from masculine and feminine in two ways: the plural nominative and accusative forms end in -a, e.g. bella "wars", corpora "bodies"; the subject and object cases are identical.

Case

Nouns in Latin have a series of different forms, called cases of the noun, which have different functions or meanings. For example, the word for "king" is rēx when it is the subject of a verb, but rēgem when it is the object:

rēx videt "the king sees"
rēgem videt " sees the king"

Further cases mean "of", "to/for", and "with".
Nouns for people have a separate form used for addressing a person. In most nouns for women and girls, the vocative is the same as the nominative.
Some nouns, such as the names of cities and small islands, and the word domus "home", have a seventh case called the locative, for example Rōmae "in Rome" or domī "at home"; however, most nouns do not have this case.
The genitive, dative and ablative cases are called the "oblique" cases.
The order in which the cases are given in grammar books differs in different countries. In Britain and countries influenced by Britain, the order nominative, vocative, accusative is used as in the table below. In the United States, in grammars such as Gildersleeve and Lodge's Latin Grammar, the traditional order is used, with the genitive case in the second place and ablative last. In the popularly used Wheelock's Latin and Allen and Greenough's New Latin Grammar, however, the vocative is placed at the end.
The following table shows the endings of a typical noun of the 3rd declension. If Gildersleeve and Lodge's order is preferred, click on the symbol "GL" in the seventh column in the table below; for Wheelock's order click on "Wh":

Name of case	Use	sing.	meaning	plur.	meaning	Br	GL	Wh
Nominative	Subject	rēx	a king, the king	rēgēs	kings, the kings	1	1	1
Vocative	Addressing	rēx	o king!	rēgēs	o kings!	2	5	6
Accusative	Object, goal	rēgem	a king, the king	rēgēs	kings, the kings	3	4	4
Genitive	of	rēgis	of the king, of a king	rēgum	of kings, of the kings	4	2	2
Dative	to, for	rēgī	to the king	rēgibus	to kings, to the kings	5	3	3
Ablative	with, by, from, in	rēge	with the king	rēgibus	with the kings	6	6	5

Sometimes the same endings, e.g. -ēs and -ibus, are used for more than one case. Since the function of a word in Latin is shown by ending rather than word order, in theory rēgēs dūcunt could mean either "the kings lead" or "they lead the kings". In practice, however, such ambiguities are rare.

Declensions

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 puella "girl", are known as "1st declension nouns", and so on.
The following table shows the declension of puella "girl", dominus "lord, master", and bellum "war" :
1st declension nouns are usually feminine, except for a few referring to men, such as agricola "farmer" or poēta "poet". The nouns fīlia "daughter" and dea "goddess" have dative and ablative plural fīliābus, deābus. The locative case ends in -ae, pl. -īs, e.g. Rōmae "in Rome", Athēnīs "in Athens".
2nd declension nouns in -us are usually masculine, but those referring to trees and some place names are feminine. A few 2nd declension nouns, such as vir "man" and 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: deum or deōrum "of the gods", virum or virōrum "of men".
Neuter nouns such as 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 vīrus "poison" and vulgus "crowd" end in -us.

3rd declension

Third declension nouns have various patterns of declension. Some decline like the following: mīles "soldier", urbs "city", corpus "body":
There are some variations, however. A few, such as vīs, vim, vī "force", have accusative singular -im and ablative singular -ī; some, like ignis "fire", optionally have -ī instead of -e in the ablative singular. The genitive plural in some nouns is -um, in others -ium. 3rd declension nouns can be of any gender.
It is not usually possible to guess the genitive of a noun from the nominative: dux "leader" has genitive ducis but rēx "king" has rēgis; pater "father" has genitive patris but iter "journey" has itineris. For this reason the genitive is always given in dictionaries, and can be used to deduce the remaining cases.