Latin declension

Latin declension is the set of patterns according to which Latin words are declined, or have their endings altered to show grammatical case, number and gender. Nouns, pronouns, and adjectives are declined (verbs are conjugated), and a given pattern is called a declension. There are five declensions, which are numbered and grouped by ending and grammatical gender. Each noun follows one of the five declensions, but some irregular nouns have exceptions.

Adjectives are of two kinds: those like bonus, bona, bonum 'good' use first-declension endings for the feminine, and second-declension for masculine and neuter. Other adjectives such as celer, celeris, celere belong to the third declension. There are no fourth- or fifth-declension adjectives.

Pronouns are also of two kinds, the personal pronouns such as ego 'I' and tū 'you (sg.)', which have their own irregular declension, and the third-person pronouns such as hic 'this' and ille 'that' which can generally be used either as pronouns or adjectivally. These latter decline in a similar way to the first and second noun declensions, but there are differences; for example the genitive singular ends in -īus or -ius instead of -ī or -ae.

The cardinal numbers ūnus 'one', duo 'two', and trēs 'three' also have their own declensions (ūnus has genitive -īus like a pronoun), and there are also numeral adjectives such as bīnī 'a pair, two each', which decline like ordinary adjectives.

Grammatical cases

A complete Latin noun declension consists of up to seven grammatical cases: nominative, vocative, accusative, genitive, dative, ablative and locative. However, the locative is limited to few nouns: generally names of cities, small islands and a few other words.

The case names are often abbreviated to the first three letters.

Order of cases

The grammarian Aelius Donatus (4th century AD), whose work was used as standard throughout the Middle Ages, placed the cases in this order:

casus sunt sex: nominativus, genetivus, dativus, accusativus, vocativus, ablativus.

"There are six cases: nominative, genitive, dative, accusative, vocative and ablative."

This order was based on the order used by earlier Greek grammarians, with the addition of the ablative, which does not exist in Greek. The names of the cases also were mostly translated from the Greek terms, such as accusativus from the Greek αἰτιατική.

The traditional order was formerly used in England, for example in The School and University Eton Latin Grammar (1861). and it is also still used in Germany and most European countries. Gildersleeve and Lodge's Latin Grammar of 1895, also follows this order. More recent American grammars, such as Allen and Greenough's New Latin Grammar (1903) and Wheelock's Latin (first published in 1956), use this order but with the vocative at the end.

However, in Britain and countries influenced by Britain, the Latin cases are usually given in the following order: nominative, vocative, accusative, genitive, dative, ablative. This order was first introduced in Benjamin Hall Kennedy's Latin Primer (1866), with the aim of making tables of declensions easier to recite and memorise. It is also used in France and Belgium.

Syncretism

Syncretism, where one form in a paradigm shares the ending of another form in the paradigm, is common in Latin. The following are the most notable patterns of syncretism:

Gender-specific

• For pure Latin neuter nouns, the nominative singular, vocative singular, and accusative singular are identical; and the nominative plural, vocative plural, and accusative plural all end in -a. (Both of these features are inherited from Proto-Indo-European, and so no actual syncretism is known to have happened in the historical sense, since these cases of these nouns are not known to have ever been different in the first place.)

Case-specific

• The vocative form is always the same as the nominative in the plural, and usually the same as the nominative in the singular except for second-declension masculine nouns ending in -us and a few nouns of Greek origin. For example, the vocative of the first-declension Aenēās is Aenēā.
• The genitive singular is the same as the nominative plural in first-, second-, and fourth-declension masculine and feminine pure Latin nouns.
• The dative singular is the same as the genitive singular in first- and fifth-declension pure Latin nouns.
• The dative is always the same as the ablative in the singular in the second declension, the third-declension full i-stems (i.e. neuter i-stems, adjectives), and fourth-declension neuters.
• The dative, ablative, and locative are always identical in the plural.
• The locative is identical to the ablative in the fourth and fifth declensions.

History of cases

Old Latin had essentially two patterns of endings. One pattern was shared by the first and second declensions, which derived from the Proto-Indo-European thematic declension. The other pattern was used by the third, fourth and fifth declensions, and derived from the athematic PIE declension.

Nouns

There are two principal parts for Latin nouns: the nominative singular and the genitive singular. Each declension can be unequivocally identified by the ending of the genitive singular (-ae, -i, -is, -ūs, -ei). The stem of the noun can be identified by the form of the genitive singular as well.

There are five declensions for Latin nouns:

First declension (a stems)

Nouns of this declension usually end in -a in the nominative singular and are mostly feminine, e.g. via, viae f. ('road') and aqua, aquae f. ('water'). There is a small class of masculine exceptions generally referring to occupations, e.g. poēta, poētae m. ('poet'), agricola, agricolae m. ('farmer') and nauta, nautae m. ('sailor').

The predominant letter in the ending forms of this declension is a. The nominative singular form consists of the stem and the ending -a, and the genitive singular form is the stem plus -ae.

	First declension paradigm
	Singular	Plural
Nominative	-a	-ae
Vocative
Accusative	-am	-ās
Genitive	-ae	-ārum
Dative		-īs
Ablative	-ā

	mensa, mensae table (f.)		poēta, poētae poet (m.)
	Singular	Plural	Singular	Plural
Nominative	mensa	mensae	poēta	poētae
Vocative
Accusative	mensam	mensās	poētam	poētās
Genitive	mensae	mensārum	poētae	poētārum
Dative		mensīs		poētīs
Ablative	mensā		poētā

The locative endings for the first declension are -ae (singular) and -īs (plural), similar to the genitive singular and ablative plural, as in mīlitiae 'in war' and Athēnīs 'at Athens'.

First declension Greek nouns

Main article: Declension of Greek nouns in Latin

The first declension also includes three types of Greek loanwords, derived from Ancient Greek's alpha declension. They are declined irregularly in the singular, but sometimes treated as native Latin nouns, e.g. nominative athlēta ('athlete') instead of the original athlētēs. Archaic (Homeric) first declension Greek nouns and adjectives had been formed in exactly the same way as in Latin: nephelēgeréta Zeus ('Zeus the cloud-gatherer') had in classical Greek become nephelēgerétēs.

For full paradigm tables and more detailed information, see the Wiktionary appendix First declension.

Second declension (o stems)

The second declension is a large group of nouns consisting of mostly masculine nouns like equus, equī ('horse') and puer, puerī ('boy') and neuter nouns like castellum, castellī ('fort'). There are several small groups of feminine exceptions, including names of gemstones, plants, trees, and some towns and cities.

In the nominative singular, most masculine nouns consist of the stem and the ending -us, although some end in -er, which is not necessarily attached to the complete stem. Neuter nouns generally have a nominative singular consisting of the stem and the ending -um. However, every second-declension noun has the ending -ī attached as a suffix to the root of the noun in the genitive singular form. The predominant letter in the ending forms of this declension is o.

	Second declension paradigm
	Singular		Plural
	Masculine	Neuter	Masculine	Neuter
Nominative	-us	-um	-ī	-a
Vocative	-e
Accusative	-um		-ōs
Genitive	-ī		-ōrum
Dative	-ō		-īs
Ablative

Masculine

	dominus, dominī master m.
	Singular	Plural
Nominative	dominus	dominī
Vocative	domine
Accusative	dominum	dominōs
Genitive	dominī	dominōrum
Dative	dominō	dominīs
Ablative

Neuter

	bellum, bellī war n.
	Singular	Plural
Nominative	bellum	bella
Accusative
Genitive	bellī	bellōrum
Dative	bellō	bellīs
Ablative

The locative endings for the second declension are -ī (singular) and -īs (plural); Corinthī "at Corinth", Mediolānī "at Milan", and Philippīs "at Philippi".

Second-declension -ius and -ium nouns

Nouns ending in -ius and -ium have a genitive singular in -ī in earlier Latin, which was regularized to -iī in the later language. Masculine nouns in -ius have a vocative singular in -ī at all stages. These forms in -ī are stressed on the same syllable as the nominative singular, sometimes in violation of the usual Latin stress rule. For example, the genitive and vocative singular Vergilī (from Vergilius) is pronounced Vergílī, with stress on the penult, even though it is short. In Old Latin, however, the vocative was declined regularly, using -ie instead, e.g. fīlie "[O] son", archaic vocative of fīlius.

There is no contraction of -iī(s) in plural forms and in the locative.

	fīlius, filiī son m.		auxilium, auxiliī aid, help n.
	Singular	Plural	Singular	Plural
Nominative	fīlius	fīliī	auxilium	auxilia
Vocative	fīlī
Accusative	fīlium	fīliōs
Genitive	fīliī	fīliōrum	auxiliī	auxiliōrum
Dative	fīliō	fīliīs	auxiliō	auxiliīs
Ablative

In the older language, nouns ending with -vus, -quus and -vum take o rather than u in the nominative and accusative singular. For example, servus, servī ('slave') could be servos, accusative servom.

Second-declension -r nouns

Some masculine nouns of the second declension end in -er or -ir in the nominative singular. The declension of these nouns is identical to that of the regular second declension, except for the lack of suffix in the nominative and vocative singular.

Some (but not all) nouns in -er drop the e genitive and other cases. For example, socer, socerī ('father-in-law') keeps its e. However, the noun magister, magistrī ('(school)master') drops its e in the genitive singular.

For declension tables of second-declension nouns, see the corresponding Wiktionary appendix.

	puer, puerī boy m.		ager, agrī field m.		vir, virī man m.
	Singular	Plural	Singular	Plural	Singular	Plural
Nominative	puer	puerī	ager	agrī	vir	virī
Vocative
Accusative	puerum	puerōs	agrum	agrōs	virum	virōs
Genitive	puerī	puerōrum	agrī	agrōrum	virī	virōrum (virum)
Dative	puerō	puerīs	agrō	agrīs	virō	virīs
Ablative

The vocative puere is found but only in Plautus. The genitive plural virum is found in poetry.

Second-declension Greek nouns

Main article: Declension of Greek nouns in Latin

The second declension contains two types of masculine Greek nouns and one form of neuter Greek noun. These nouns are irregular only in the singular, as are their first-declension counterparts. Greek nouns in the second declension are derived from the Omicron declension.

Some Greek nouns may also be declined as normal Latin nouns. For example, theātron can appear as theātrum.

Irregular forms

Deus

The inflection of deus, deī ('god') is irregular. The vocative singular of deus is not attested in Classical Latin. In Ecclesiastical Latin the vocative of Deus ('God') is Deus.

In poetry, -um may substitute -ōrum as the genitive plural ending.

	deus, deī god m.
	Singular	Plural
Nominative	deus	deī diī dī
Accusative	deum	deōs
Genitive	deī	deōrum deum
Dative	deō	deīs diīs dīs
Ablative

Virus

The Latin word vīrus (the ī indicates a long i) means "1. slimy liquid, slime; 2. poison, venom", denoting the venom of a snake. This Latin word is probably related to the Greek ῑ̓ός (ios) meaning "venom" or "rust" and the Sanskrit word विष viṣa meaning "toxic, poison".

Since vīrus in antiquity denoted something uncountable, it was a mass noun. Mass nouns pluralize only under special circumstances, hence the non-existence of plural forms in the texts.

In Neo-Latin, a plural form is necessary in order to express the modern concept of ‘viruses’, which leads to the following declension:

	vīrus, vīrī poison, venom, virus n.
	Singular	Plural
Nominative	vīrus	vīra
Accusative
Genitive	vīrī	vīrōrum
Dative	vīrō	vīrīs
Ablative

Third declension

The third declension is the largest group of nouns. The nominative singular of these nouns may end in -a, -e, -ī, -ō, -y, -c, -l, -n, -r, -s, -t, or -x. This group of nouns includes masculine, neuter, and feminine nouns.

Consonant stems

The stem of a consonant-stem noun may be found from the genitive case by removing the ending -is. For example, the stem of pāx, pācis f. 'peace' is pāc-, the stem of flūmen, flūminis n. 'river' is flūmin-, and the stem of flōs, flōris m. 'flower' is flōr-.

Masculine, feminine and neuter nouns often have their own special nominative singular endings. For instance, many masculine nouns end in -or (amor, amōris, 'love'). Many feminine nouns end in -īx (phoenīx, phoenīcis, 'phoenix'), and many neuter nouns end in -us with an r stem in the oblique cases (onus, oneris 'burden'; tempus, temporis 'time').

	Third declension paradigm (consonant stems)
	Masculine & feminine		Neuter
	Singular	Plural	Singular	Plural
Nominative	(-s)	-ēs	—	-a
Accusative	-em
Genitive	-is	-um	-is	-um
Dative	-ī	-ibus	-ī	-ibus
Ablative	-e		-e

	dux, ducis leader m.		virtūs, virtūtis virtue f.		nōmen, nōminis name n.
	Singular	Plural	Singular	Plural	Singular	Plural
Nominative	dux	ducēs	virtūs	virtūtēs	nōmen	nōmina
Accusative	ducem		virtūtem
Genitive	ducis	ducum	virtūtis	virtūtum	nōminis	nōminum
Dative	ducī	ducibus	virtūtī	virtūtibus	nōminī	nōminibus
Ablative	duce		virtūte		nōmine

The locative endings for the third declension are -ī or -e (singular) and -ibus (plural), as in rūrī 'in the country' and Trallibus 'at Tralles'.

Third declension i-stem and mixed nouns

The third declension also has a set of nouns that are declined differently. They are called i-stems. i-stems are broken into two subcategories: pure and mixed. Pure i-stems are indicated by special neuter endings. Mixed i-stems are indicated by the double consonant rule. Stems indicated by the parisyllabic rule are usually mixed, occasionally pure.

Masculine and feminine

Parisyllabic rule: Some masculine and feminine third-declension i-stem nouns have the same number of syllables in the genitive as they do in the nominative. For example: nāvis, nāvis ('ship'); nūbēs, nūbis ('cloud'). The nominative ends in -is or -ēs.

Double consonant rule: The rest of the masculine and feminine third-declension i-stem nouns have two consonants before the -is in the genitive singular. For example: pars, partis ('part').

Neuter

Special neuter ending: Neuter third-declension i-stems have no rule. However, all of them end in -al, -ar or -e. For example: animal, animālis ('animal'); cochlear, cochleāris ('spoon'); mare, maris ('sea').

The mixed declension is distinguished from the consonant type only by having -ium in the genitive plural (and occasionally -īs in the accusative plural). The pure declension is characterized by having -ī in the ablative singular, -ium in the genitive plural, -ia in the nominative and accusative plural neuter, and -im in the accusative singular masculine and feminine (however, adjectives have -em).

The accusative plural ending -īs is found in early Latin up to Virgil, but from the early empire onwards it was replaced by -ēs.

The accusative singular ending -im is found only in a few words: always in tussis 'cough', sitis 'thirst', Tiberis 'River Tiber'; usually in secūris 'axe', turris 'tower'; occasionally in nāvis 'ship'. Most nouns, however, have accusative singular -em.

The ablative singular -ī is found in nouns which have -im, and also, optionally, in some other nouns, e.g. in ignī or in igne 'in the fire'.

There are two mixed-declension neuter nouns: cor, cordis ('heart') and os, ossis ('bone'). Also, the mixed declension is used in the plural-only adjective plūrēs, plūra ('most').

	Third declension paradigm (i-stem nouns)
	Masculine & Feminine		Neuter
	Singular	Plural	Singular	Plural
Nominative	—	-ēs	—	-ia
Accusative	-em -im	-ēs -īs
Genitive	-is	-ium	-is	-ium
Dative	-ī	-ibus	-ī	-ibus
Ablative	-e -ī

	Third declension paradigm (mixed nouns)
	Masculine & Feminine		Neuter
	Singular	Plural	Singular	Plural
Nominative	—	-ēs	—	-a
Accusative	-em	-ēs -īs
Genitive	-is	-ium	-is	-ium
Dative	-ī	-ibus	-ī	-ibus
Ablative	-e		-e

	turris, turris tower f. (pure)		pars, partis part, piece f. (mixed)		animal, animālis animal, living being n. (pure)
	Parisyllabic rule		Double consonant rule		Special neuter ending
	Singular	Plural	Singular	Plural	Singular	Plural
Nominative	turris	turrēs	pars	partēs	animal	animālia
Accusative	turrem turrim	turrēs turrīs	partem	partēs partīs
Genitive	turris	turrium	partis	partium	animālis	animālium
Dative	turrī	turribus	partī	partibus	animālī	animālibus
Ablative	turre turrī		parte (partī)

The rules for determining i-stems from non-i-stems and mixed i-stems are guidelines rather than rules: many words that might be expected to be i-stems according to the parisyllabic rule actually are not, such as canis ('dog') or iuvenis ('youth'), which have genitive plural canum 'of dogs' and iuvenum 'of young men'. Likewise, pater ('father'), māter ('mother'), frāter ('brother'), and parēns ('parent') violate the double-consonant rule. This fluidity even in Roman times resulted in much more uncertainty in Medieval Latin.

Some nouns in -tāt-, such as cīvitās, cīvitātis 'city, community' can have either consonant-stem or i-stem genitive plural: cīvitātum or cīvitātium 'of the cities'.

Peculiarities

In the third declension, there are four irregular nouns.

Case	vīs, vīs force, power f.		sūs, suis swine, pig, hog m.f.		bōs, bovis ox, bullock m.f.		Iuppiter, Iovis Jupiter m.
	Singular	Plural	Singular	Plural	Singular	Plural	Singular
Nominative	vīs	vīrēs	sūs	suēs	bōs	bovēs	Iuppiter Iūpiter
Accusative	vim	vīrēs vīrīs	suem		bovem		Iovem
Genitive	vīs	vīrium	suis	suum	bovis	boum bovum	Iovis
Dative	vī	vīribus	suī	suibus sūbus	bovī	bōbus būbus	Iovī
Ablative			sue		bove		Iove

Fourth declension (u stems)

The fourth declension is a group of nouns consisting of mostly masculine words such as fluctus, fluctūs m. ('wave') and portus, portūs m. ('port') with a few feminine exceptions, including manus, manūs f. ('hand'). The fourth declension also includes several neuter nouns including genū, genūs n. ('knee'). Each noun has the ending -ūs as a suffix attached to the root of the noun in the genitive singular form. The predominant letter in the ending forms of this declension is u, but the declension is otherwise very similar to the third-declension i stems.

	Fourth declension paradigm
	-us ending nouns		-ū ending nouns
	Singular	Plural	Singular	Plural
Nominative	-us	-ūs	-ū	-ua
Accusative	-um
Genitive	-ūs	-uum	-ūs -ū	-uum
Dative	-uī	-ibus	-uī -ū	-ibus
Ablative	-ū		-ū

	portus, portūs port, haven, harbor m.		cornū, cornūs horn n.
	Singular	Plural	Singular	Plural
Nominative	portus	portūs	cornū	cornua
Accusative	portum
Genitive	portūs	portuum	cornūs cornū	cornuum
Dative	portuī	portibus	cornuī cornū	cornibus
Ablative	portū		cornū

In the dative and ablative plural, -ibus is sometimes replaced with -ubus. This is so for only a few nouns, such as artūs pl., ('limbs').

The locative endings for the fourth declension are -ī (singular), and probably -ū (singular) as well; senātī "at [the] senate", domī "at home".

Domus ('house, dwelling, building, home, native place, family, household, race') is an irregular noun, mixing fourth and second declension nouns at the same time (especially in literature). However, in practice, it is generally declined as a regular -us stem fourth declension noun (except by the ablative singular and accusative plural, using -ō and -ōs instead).

	domus, domūs/domī f.
	All possible declensions
	Singular	Plural
Nominative	domus	domūs
Accusative	domum	domūs domōs
Genitive	domūs domī	domuum domōrum
Dative	domuī domū domō	domibus
Ablative	domū domō

	domus, domūs f.
	Most common paradigm
	Singular	Plural
Nominative	domus	domūs
Accusative	domum	domōs
Genitive	domūs	domuum
Dative	domuī	domibus
Ablative	domō

Fifth declension (e stems)

The fifth declension is a small group of nouns consisting of mostly feminine nouns like rēs, reī f. ('affair, matter, thing') and diēs, diēī m. ('day'; but f. in names of days). Each noun has either the ending -ēī or -eī as a suffix attached to the root of the noun in the genitive singular form.

	Fifth declension paradigm
	-iēs ending nouns		-ēs ending nouns
	Singular	Plural	Singular	Plural
Nominative	-iēs	-iēs	-ēs	-ēs
Accusative	-iem		-em
Genitive	-iēī	-iērum	-eī	-ērum
Dative		-iēbus		-ēbus
Ablative	-iē		-ē

	diēs, diēī day m., f.		rēs, reī thing f.
	Singular	Plural	Singular	Plural
Nominative	diēs	diēs	rēs	rēs
Accusative	diem		rem
Genitive	diēī	diērum	reī	rērum
Dative		diēbus		rēbus
Ablative	diē		rē

Nouns ending in -iēs have long ēī in the dative and genitive, while nouns ending in a consonant + -ēs have short eī in these cases.

The locative ending of the fifth declension was -ē (singular only), identical to the ablative singular, as in hodiē ('today').

Pronouns

Personal pronouns

The first and second persons are irregular, and both pronouns are indeclinable for gender; and the third person reflexive pronoun sē, suī always refers back to the subject, regardless of whether the subject is singular or plural.

	First Person		Second Person		Third Person
	ego, nōs I, we		tū, vōs you		sē, suī himself, herself, itself, oneself, themselves
	Singular	Plural	Singular	Plural	Singular	Plural
Nominative	ego egō	nōs	tū	vōs	—
Accusative	mē		tē		sē sēsē
Genitive	meī	nostrī, nostrum	tuī	vestrī, vestrum	suī
Dative	mihi mihī	nōbīs	tibi tibī	vōbīs	sibi sibī
Ablative	mē		tē		sē sēsē

The genitive forms meī, tuī, nostrī, vestrī, suī are used as complements in certain grammatical constructions, whereas nostrum, vestrum are used with a partitive meaning ('[one] of us', '[one] of you'). To express possession, the possessive pronouns (essentially adjectives) meus, tuus, noster, vester are used, declined in the first and second declensions to agree in number and case with the thing possessed, e.g. pater meus 'my father', māter mea 'my mother'. The vocative singular masculine of meus is mī: mī Attice 'my dear Atticus'.

Possessive pronouns' declensions

	meus, mea, meum my, mine
	Singular			Plural
	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	meus	mea	meum	meī	meae	mea
Vocative	mī
Accusative	meum	meam		meōs	meās
Genitive	meī	meae	meī	meōrum	meārum	meōrum
Dative	meō		meō	meīs
Ablative		meā

	tuus, tua, tuum your, yours (for singular possessor)
	Singular			Plural
	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	tuus	tua	tuum	tuī	tuae	tua
Accusative	tuum	tuam		tuōs	tuās
Genitive	tuī	tuae	tuī	tuōrum	tuārum	tuōrum
Dative	tuō		tuō	tuīs
Ablative		tuā

	suus, sua, suum his, her, its, theirs (reflexive)
	Singular			Plural
	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	suus	sua	suum	suī	suae	sua
Accusative	suum	suam		suōs	suās
Genitive	suī	suae	suī	suōrum	suārum	suōrum
Dative	suō		suō	suīs
Ablative		suā

	noster, nostra, nostrum our, ours
	Singular			Plural
	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	noster	nostra	nostrum	nostrī	nostrae	nostra
Accusative	nostrum	nostram		nostrōs	nostrās
Genitive	nostrī	nostrae	nostrī	nostrōrum	nostrārum	nostrōrum
Dative	nostrō		nostrō	nostrīs
Ablative		nostrā

The possessive adjective vester has an archaic variant, voster; similar to noster.

	vester, vestra, vestrum voster, vostra, vostrum your, yours (for plural possessor)
	Singular			Plural
	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	vester voster	vestra vostra	vestrum vostrum	vestrī vostrī	vestrae vostrae	vestra vostra
Accusative	vestrum vostrum	vestram vostram		vestrōs vostrōs	vestrās vostrās
Genitive	vestrī vostrī	vestrae vostrae	vestrī vostrī	vestrōrum vostrōrum	vestrārum vostrārum	vestrōrum vostrōrum
Dative	vestrō vostrō		vestrō vostrō	vestrīs vostrīs
Ablative		vestrā vostrā

Usually, to show the ablative of accompaniment, cum would be added to the ablative form. However, with personal pronouns (first and second person), the reflexive and the interrogative, -cum is added onto the end of the ablative form. That is: mēcum 'with me', nōbīscum 'with us', tēcum 'with you', vōbīscum, sēcum and quōcum (sometimes quīcum).

Pronouns have also an emphatic form bi using the suffix -met (egomet, tūte/tūtemet, nosmet, vosmet), used in all cases, except by the genitive plural forms.

In accusative case, the forms mēmē and tētē exist as emphatic, but they are not widely used.

Sē, suī has a possessive adjective: suus, sua, suum, meaning 'his/her/its/their own':

Patrem suum numquam vīderat. (Cicero)

"He had never seen his [own] father."

When 'his' or 'her' refers to someone else, not the subject, the genitive pronoun eius (as well as eōrum and eārum) 'of him' is used instead of suus:

Fit obviam Clodiō ante fundum eius. (Cicero)

"He met Clodius in front of the latter's farm."

When one sentence is embedded inside another with a different subject, sē and suus can refer to either subject:

Patrēs conscrīptī ... lēgātōs in Bīthȳniam miserunt quī ab rēge peterent, nē inimīcissimum suum secum haberet sibique dēderet. (Nepos)

"The senators ... sent ambassadors to Bithynia, who were to ask the king not to keep their greatest enemy with him but hand him over to them."

For the third-person pronoun is 'he', see below.

Demonstrative pronouns and adjectives

Relative, demonstrative and indefinite pronouns are generally declined like first and second declension adjectives, with the following differences:

• the nominatives are often irregular
• the genitive singular ends in -īus rather than -ae or -ī.
• the dative singular ends in -ī: rather than -ae or -ō.

These differences characterize the pronominal declension, and a few special adjectives (tōtus 'whole', sōlus 'alone', ūnus 'one', nūllus 'no', alius 'another', alter 'another [of two]', etc.) are also declined according to this pattern.

All demonstrative, relative, and indefinite pronouns in Latin can also be used adjectivally, with some small differences; for example in the interrogative pronoun, quis 'who?' and quid 'what?' are usually used for the pronominal form, quī and quod 'which?' for the adjectival form.

Third person pronoun

The weak demonstrative pronoun is, ea, id 'that' also serves as the third person pronoun 'he, she, it':

	Third person
	is, ea, id he, she, it
	Singular			Plural
	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	is	ea	id	eī iī	eae	ea
Accusative	eum	eam		eōs	eās
Genitive	eius			eōrum	eārum	eōrum
Dative	eī			eīs iīs
Ablative	eō	eā	eō

This pronoun is also often used adjectivally, e.g. is homo 'that man', ea pecunia 'that money'. It has no possessive adjective; the genitive is used instead: pater eius 'his/her father'; pater eōrum 'their father'.

Declension of īdem

The pronoun or pronominal adjective īdem, eadem, idem means 'the same'. It is derived from is with the suffix -dem. However, some forms have been assimilated.

	īdem, eadem, idem the same, same as
	Singular			Plural
	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	īdem	eadem	idem	eīdem īdem iīdem	eaedem	eadem
Accusative	eundem	eandem		eōsdem	eāsdem
Genitive	eiusdem			eōrundem	eārundem	eōrundem
Dative	eīdem			eīsdem īsdem iīsdem
Ablative	eōdem	eādem	eōdem

Other demonstrative pronouns

	hic, haec, hoc this, this one (proximal)						ille, illa, illud that, that one (distal)						iste, ista, istud that of yours (medial)
	Singular			Plural			Singular			Plural			Singular			Plural
	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	hic	haec	hoc	hī	hae	haec	ille	illa	illud	illī	illae	illa	iste	ista	istud	istī	istae	ista
Accusative	hunc	hanc		hōs	hās		illum	illam		illōs	illās		istum	istam		istōs	istās
Genitive	huius			hōrum	hārum	hōrum	illīus			illōrum	illārum	illōrum	istīus			istōrum	istārum	istōrum
Dative	huic			hīs			illī			illīs			istī			istīs
Ablative	hōc	hāc	hōc				illō	illā	illō				istō	istā	istō

Similar in declension is alius, alia, aliud 'another'.

Intensive pronoun

	ipse, ipsa, ipsum himself, herself, itself
	Singular			Plural
	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	ipse	ipsa	ipsum	ipsi	ipsae	ipsa
Accusative	ipsum	ipsam		ipsōs	ipsās
Genitive	ipsīus			ipsōrum	ipsārum	ipsōrum
Dative	ipsī			ipsīs
Ablative	ipsō	ipsā	ipsō

Interrogative pronouns

The interrogative pronouns are used strictly for asking questions. They are distinct from the relative pronoun and the interrogative adjective (which is declined like the relative pronoun). Interrogative pronouns rarely occur in the plural. The plural interrogative pronouns are the same as the plural relative pronouns.

Singular

	quis? quid? who?, what?
	Masculine & Feminine	Neuter
Nominative	quis?	quid?
Accusative	quem?
Genitive	cuius?
Dative	cuī?
Ablative	quō?

Relative pronouns

	quī, quae, quod who, which, that
	Singular			Plural
	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	quī	quae	quod	quī	quae	quae
Accusative	quem	quam		quōs	quās
Genitive	cuius			quōrum	quārum	quōrum
Dative	cuī			quibus
Ablative	quō	quā	quō

Adjectives

First- and second-declension adjectives

First- and second-declension adjectives are inflected in the masculine, the feminine and the neuter; the masculine form typically ends in -us (although some end in -er, see below), the feminine form ends in -a, and the neuter form ends in -um. Therefore, some adjectives are given like altus, alta, altum.

Adjectives ending -ius use the vocative -ie (ēbrie, "[O] drunk man", vocative of ēbrius), just as in Old Latin all -ius nouns did (fīlie, "[O] son", archaic vocative of fīlius).

	altus, alta, altum high, long, tall
	Singular			Plural
	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	altus	alta	altum	altī	altae	alta
Vocative	alte
Accusative	altum	altam		altōs	altās
Genitive	altī	altae	altī	altōrum	altārum	altōrum
Dative	altō		altō	altīs
Ablative		altā

First- and second-declension -r adjectives

Some first- and second-declension adjectives' masculine forms end in -er. As with second-declension -r nouns, some adjectives retain the e throughout inflection, and some omit it. Sacer, sacra, sacrum omits its e while miser, misera, miserum keeps it.

	miser, misera, miserum sad, poor, unhappy
	Singular			Plural
	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	miser	misera	miserum	miserī	miserae	misera
Accusative	miserum	miseram		miserōs	miserās
Genitive	miserī	miserae	miserī	miserōrum	miserārum	miserōrum
Dative	miserō		miserō	miserīs
Ablative		miserā

	sacer, sacra, sacrum sacred, holy
	Singular			Plural
	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	sacer	sacra	sacrum	sacrī	sacrae	sacra
Accusative	sacrum	sacram		sacrōs	sacrās
Genitive	sacrī	sacrae	sacrī	sacrōrum	sacrārum	sacrōrum
Dative	sacrō		sacrō	sacrīs
Ablative		sacrā

First and second declension pronominal adjectives

Nine first and second declension pronominal adjectives are irregular in the genitive and the dative in all genders. They can be remembered by using the mnemonic acronym ūnus nauta. They are:

• ūllus, ūlla, ūllum 'any';
• nūllus, nūlla, nūllum 'no, none';
• uter, utra, utrum 'which [of two], either';
• sōlus, sōla, sōlum 'sole, alone';
• neuter, neutra, neutrum 'neither';
• alius, alia, aliud 'another' (the genitive singular alīus is often replaced by alterīus or by aliēnus 'of another');
• ūnus, ūna, ūnum 'one';
• tōtus, tōta, tōtum 'whole';
• alter, altera, alterum 'other [of two]'.

	ūllus, ūlla, ūllum any
	Singular			Plural
	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	ūllus	ūlla	ūllum	ūllī	ūllae	ūlla
Accusative	ūllum	ūllam		ūllōs	ūllās
Genitive	ūllīus			ūllōrum	ūllārum	ūllōrum
Dative	ūllī			ūllīs
Ablative	ūllō	ūllā	ūllō

Third-declension adjectives

Third-declension adjectives are normally declined like third-declension i-stem nouns, except for the fact they usually have -ī rather than -e in the ablative singular (unlike i-stem nouns, in which only pure i-stems have -ī). Some adjectives, however, like the one-ending vetus, veteris ('old, aged'), have -e in the ablative singular, -um in the genitive plural, and -a in the nominative and accusative neuter plural.

Third-declension adjectives with one ending

These have a single nominative ending for all genders, although as usual the endings for the other cases vary. As with nouns, a genitive is given for the purpose of showing the inflection.

	atrōx, atrōx terrible, mean, cruel
	Singular		Plural
	Masculine & Feminine	Neuter	Masculine & Feminine	Neuter
Nominative	atrōx	atrōx	atrōcēs	atrōcia
Accusative	atrōcem		atrōcēs atrōcīs
Genitive	atrōcis		atrōcium
Dative Ablative	atrōcī		atrōcibus

Non-i-stem variant

	vetus, vetus old, aged
	Singular		Plural
	Masculine & Feminine	Neuter	Masculine & Feminine	Neuter
Nominative	vetus	vetus	veterēs	vetera
Accusative	veterem
Genitive	veteris		veterum
Dative	veterī		veteribus
Ablative	vetere

Third-declension adjectives with two endings

Third-declension adjectives that have two endings have one form for the masculine and feminine, and a separate form for the neuter. The ending for the masculine and feminine is -is, and the ending for the neuter is -e. It is not necessary to give the genitive, as it is the same as the nominative masculine singular.

	agilis, agile nimble, swift
	Singular		Plural
	Masculine & Feminine	Neuter	Masculine & Feminine	Neuter
Nominative	agilis	agile	agilēs	agilia
Accusative	agilem		agilēs agilīs
Genitive	agilis		agilium
Dative Ablative	agilī		agilibus

Third-declension adjectives with three endings

Third-declension adjectives with three endings have three separate nominative forms for all three genders. Like third and second declension -r nouns, the masculine ends in -er. The feminine ends in -ris, and the neuter ends in -re. The genitive is the same as the nominative feminine singular.

	celer, celeris, celere swift, rapid, brash
	Singular			Plural
	Masculine	Feminine	Neuter	Masculine & Feminine	Neuter
Nominative	celer	celeris	celere	celerēs	celeria
Accusative	celerem	celerem
Genitive	celeris			celerium
Dative Ablative	celerī			celeribus

	alacer, alacris, alacre lively, jovial, animated
	Singular			Plural
	Masculine	Feminine	Neuter	Masculine & Feminine	Neuter
Nominative	alacer	alacris	alacre	alacrēs	alacria
Accusative	alacrem	alacrem		alacrēs alacrīs
Genitive	alacris			alacrium
Dative Ablative	alacrī			alacribus

Comparative and superlative forms of adjectives

As in English, adjectives have superlative and comparative forms. For regular first and second declension and third declension adjectives with one or two endings, the comparative is formed by adding -ior for the masculine and feminine, and -ius for the neuter to the stem. The genitives for both are formed by adding -iōris. Therefore, they are declined in the third declension, but they are not declined as i-stems. Superlatives are formed by adding -issimus, -issima, -issimum to the stem and are thus declined like first and second declension adjectives.

General pattern for comparatives

	altior, altius higher, deeper (comparative of altus)
	Singular		Plural
	Masculine & Feminine	Neuter	Masculine & Feminine	Neuter
Nominative	altior	altius	altiōrēs	altiōra
Accusative	altiōrem
Genitive	altiōris		altiōrum
Dative	altiōrī		altiōribus
Ablative	altiōre

	altissimus, altissima, altissimum highest, deepest (superlative of altus)
	Singular			Plural
	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	altissimus	altissima	altissimum	altissimī	altissimae	altissima
Vocative	altissime
Accusative	altissimum	altissimam		altissimōs	altissimās
Genitive	altissimī	altissimae	altissimī	altissimōrum	altissimārum	altissimōrum
Dative	altissimō		altissimō	altissimīs
Ablative		altissimā

Comparatives and superlatives with normal endings

Positive	Comparative	Superlative
clārus, clāra, clārum ('clear, bright, famous')	clārior, clārius	clārissimus, clārissima, clārissimum
frīgidus, frīgida, frīgidum ('cold, chilly')	frīgidior, frīgidius	frīgidissimus, frīgidissima, frīgidissimum
pugnāx, pugnāx (pugnācis) ('pugnacious')	pugnācior, pugnācius	pugnācissimus, pugnācissima, pugnācissimum
benevolēns, benevolēns (benevolentis) ('kind, benevolent')	benevolentior, benevolentius	benevolentissimus, benevolentissima, benevolentissium
fortis, forte ('strong, robust')	fortior, fortius	fortissimus, fortissima, fortissimum
aequālis, aequāle ('equal, even')	aequālior, aequālius	aequālissimus, aequālissima, aequālissimum

Comparatives and superlatives of -er adjectives

Adjectives (in the first and second as well as third declensions) that have masculine nominative singular forms ending in -er are slightly different. As with normal adjectives, the comparative is formed by adding -ior to the stem, but for the superlative, -rimus is added to the nominative masculine singular.

Positive	Comparative	Superlative
pulcher, pulchra, pulchrum ('pretty, beautiful')	pulchrior, pulchrius	pulcherrimus, pulcherrima, pulcherrimum
sacer, sacra, sacrum ('sacred, holy')	sacrior, sacrius	sacerrimus, sacerrima, sacerrimum
tener, tenera, tenerum ('delicate, tender')	tenerior, tenerius	tenerrimus, tenerrima, tenerrimum
ācer, ācris, ācre ('valliant, fierce')	ācrior, ācrius	ācerrimus, ācerrima, ācerrimum
celeber, celebris, celebre ('celebrated, famous')	celebrior, celebrius	celeberrimus, celeberrima, celeberrimum
celer, celeris, celere ('quick, fast')	celerior, celerius	celerrimus, celerrima, celerrimum

Comparatives and superlatives of -lis adjectives

Some third declension adjectives with two endings in -lis in the masculine–feminine nominative singular have irregular superlative forms. The following are the only adjectives that do.

Positive	Comparative	Superlative
facilis, facile ('easy')	facilior, facilius	facillimus, facillima, facillimum
difficilis, difficile ('hard, difficult')	difficilior, difficilius	difficillimus, difficillima, difficillimum
similis, simile ('similar, like)	similior, similius	simillimus, simillima, simillimum
dissimilis, dissimile ('unlike, dissimilar')	dissimilior, dissimilius	dissimillimus, dissimillima, dissimillimum
gracilis, gracile ('slender, slim')	gracilior, gracilius	gracillimus, gracillima, gracillimum
humilis, humile ('low, humble')	humilior, humilius	humillimus, humillima, humillimum

Comparatives and superlatives of -eus/-ius adjectives

First and second declension adjectives that end in -eus or -ius are unusual in that they do not form the comparative and superlative by taking endings at all. Instead, magis ('more') and maximē ('most'), the comparative and superlative degrees of magnoperē ('much, greatly'), respectively, are used.

Many adjectives in -uus, except those in -quus or -guus, also follow this rule.

Positive	Comparative	Superlative
idōneus, idōnea, idōneum ('suitable, fitting, proper')	magis idōneus	maximē idōneus
sōlitārius, sōlitāria, sōlitārium ('solitary, lonely')	magis sōlitārius	maximē sōlitārius
ebrius, ebria, ebrium ('drunk')	magis ebrius	maximē ebrius
meritōrius, meritōria, meritōrium ('meritorious')	magis meritōrius	maximē meritōrius
grāmineus, grāminea, grāmineum ('grassy')	magis grāmineus	maximē grāmineus
bellātōrius, bellātōria, bellātōrium ('warlike, bellicose')	magis bellātōrius	maximē bellātōrius
arduus, ardua, arduum ('lofty, steep')	magis arduus	maximē arduus

Irregular comparatives and superlatives

As in most languages, Latin has adjectives that have irregular comparatives and superlatives.

Positive	Comparative	Superlative
bonus, bona, bonum ('good')	melior, melius ('better')	optimus, optima, optimum ('best')
malus, mala, malum ('bad, evil')	pēior, pēius ('worse')	pessimus, pessima, pessimum ('worst')
magnus, magna, magnum ('great, large')	māior, māius ('greater')	maximus, maxima, maximum ('greatest')
parvus, parva, parvum ('small, slight')	minor, minus ('lesser')	minimus, minima, minimum ('least')
multus, multa, multum ('much, many')	plūs ('more')	plūrimus, plūrima, plūrimum ('most')
propinquus, propinqua, propinquum ('near, close')	propior, propius ('nearer')	proximus, proxima, proximum ('nearest, next')
mātūrus, mātūra, mātūrum ('ripe, mature')	mātūrior, mātūrius ('riper')	mātūrrimus, mātūrrima, mātūrrimum ('ripest')
nēquam ('worthless')	nēquior, nēquius ('more worthless')	nēquissimus, nēquissima, nēquissimum ('most worthless')
posterus, postera, posterum ('next, future')	posterior, posterius ('later')	postrēmus, postrēma, postrēmum ('last, latest') postumus, postuma, postumum
superus, supera, superum ('above')	superior, superius ('upper')	suprēmus, suprēma, suprēmum ('uppermost') summus, summa, summum
exterus, extera, exterum ('outward')	exterior, exterius ('outer')	extrēmus, extrēma, extrēmum ('outermost') extimus, extima, extimum
īnferus, īnfera, īnferum ('below')	īnferior, īnferius ('lower')	īnfimus, īnfima, īnfimum ('lowest') īmus, īma, īmum
senex, senis ('old, aged')	senior, senius ('older, elder')	senissimus, senissima, senissimum ('oldest, eldest')
iuvenis, iuvenis ('young, youthful')	iuvenior, iuvenius ('younger') iūnior, iūnius	iuvenissimus, iuvenissima, iuvenissimum ('youngest') iūnissimus, iūnissima, iūnissimum

Declension of numerals

See also: Roman numerals and Latin numerals (linguistics)

There are several different kinds of numeral words in Latin: the two most common are cardinal numerals and ordinal numerals. There are also several more rare numerals, e.g., distributive numerals and adverbial numerals.

Cardinal numerals

All cardinal numerals are indeclinable, except ūnus ('one'), duo ('two'), trēs ('three'), plural hundreds ducentī ('two hundred'), trecentī ('three hundred') etc., and mīlle ('thousand'), which have cases and genders like adjectives. Ūnus, ūna, ūnum is declined like a first- and second-declension pronoun with -īus or -ius in the genitive, and -ī in the dative. Duo is declined irregularly, trēs is declined like a third-declension plural adjective, -centī ('hundred') numerals decline like first- and second-declension adjectives, and mīlle is invariable in the singular and declined like a third-declension i-stem neuter noun in the plural:

The plural endings for ūnus are used with plūrālia tantum nouns, e. g. ūna castra (one [military] camp), ūnae scālae (one ladder).

	ūnus, ūna, ūnum one
	Singular			Plural
	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	ūnus	ūna	ūnum	ūnī	ūnae	ūna
Vocative	ūne
Accusative	ūnum	ūnam		ūnōs	ūnās
Genitive	ūnīus / ūnius			ūnōrum	ūnārum	ūnōrum
Dative	ūnī			ūnīs
Ablative	ūnō	ūnā	ūnō

The word ambō ('both'), is declined like duo except that its o is long. Both declensions derive from the Indo-European dual number, otherwise defunct in Latin, rather than the plural.

	duo, duae, duo two
	Plural
	Masculine	Feminine	Neuter
Nominative	duo	duae	duo
Accusative	duōs duo	duās
Genitive	duōrum	duārum	duōrum
Dative Ablative	duōbus	duābus	duōbus

	ambō, ambae, ambō both
	Plural
	Masculine	Feminine	Neuter
Nominative	ambō	ambae	ambō
Accusative	ambōs ambō	ambās
Genitive	ambōrum	ambārum	ambōrum
Dative Ablative	ambōbus	ambābus	ambōbus

	trēs, tria three
	Plural
	Masculine & Feminine	Neuter
Nominative	trēs	tria
Accusative	trēs / trīs
Genitive	trium
Dative Ablative	tribus

The numeral centum ('one hundred') is indeclinable, but all the other hundred numerals are declinable.

	ducentī, ducentae, ducenta two hundred
	Plural
	Masculine	Feminine	Neuter
Nominative	ducentī	ducentae	ducenta
Accusative	ducentōs	ducentās
Genitive	ducentōrum	ducentārum	ducentōrum
Dative Ablative	ducentīs

The word mīlle 'thousand' is a singular indeclinable adjective. However, its plural, mīlia, is a plural third-declension i-stem neuter noun. To write the phrase "four thousand horses" in Latin, the genitive is used: quattuor mīlia equōrum, literally, "four thousands of horses".

	mīlle (one) thousand	mīlia, mīlium x thousand, thousands
Nominative	mīlle	mīlia mīllia	-ia
Accusative
Genitive		mīlium mīllium	-ium
Dative Ablative		mīlibus mīllibus	-ibus

The rest of the numbers are indeclinable whether used as adjectives or as nouns.

For further information on the different sets of Latin numerals, see Latin numerals (linguistics).

Adverbs and their comparatives and superlatives

Adverbs are not declined. However, adverbs must be formed if one wants to make an adjective into an adverb.

Adverbs from first- and second-declension adjectives

First and second declension adjectives' adverbs are formed by adding -ē onto their stems.

Adjective	Adverb
clārus, clāra, clārum ('clear, famous')	clārē ('clearly, famously')
validus, valida, validum ('strong, robust')	validē ('strongly, robustly')
īnfīrmus, īnfīrma, īnfīrmum ('weak')	īnfīrmē ('weakly')
solidus, solida, solidum ('complete, firm')	solidē ('completely, firmly')
integer, integra, integrum ('whole, fresh')	integrē ('wholly, freshly')
līber, lībera, līberum ('free')	līberē ('freely')

Adverbs from third declension adjectives

Typically, third declension adjectives' adverbs are formed by adding -iter to the stem. However, most third declension adjectives with one ending simply add -er to the stem.

Adjective	Adverb
prūdēns, prūdēns (prūdentis) ('prudent')	prūdenter ('prudently')
audāx, audāx (audācis) ('bold')	audācter ('boldly')
virīlis, virīle ('courageous, spirited')	virīliter ('courageously, spiritedly')
salūbris, salūbre ('wholesome')	salūbriter ('wholesomely')

Comparative and superlative of adverbs

Adverbs' comparative forms are identical to the nominative neuter singular of the corresponding comparative adjective. Adverbs' superlative forms are simply formed by attaching the regular ending -ē to the corresponding superlative adjective. As with their corresponding adjectival forms, first and second declensions adjectives ending in -eus or -ius use magis and maximē as opposed to distinct endings.

Positive	Comparative	Superlative
clārē ('clearly, famously')	clārius	clārissimē
solidē ('completely, firmly')	solidius	solidissimē
idōneē ('suitably, properly')	magis idōneē	maximē idōneē
prudenter ('prudently')	prudentius	prudentissimē
salūbriter ('wholesomely')	salūbrius	salūbrissimē

Irregular adverbs and their comparative and superlative forms

As with adjectives, there are irregular adverbs with peculiar comparative and superlative forms.

Positive	Comparative	Superlative
bene ('well')	melius ('better')	optimē ('best')
male ('badly, ill')	peius ('worse')	pessimē ('worst')
magnopere ('greatly')	magis ('more')	maximē ('most')
multum ('much, a lot')	plūs ('more')	plūrimum ('most')
parvum ('little')	minus ('less')	minimē ('least')
nēquiter ('worthlessly')	nēquius ('more worthlessly')	nēquissimē ('most worthlessly')
saepe ('often')	saepius ('more often')	saepissimē ('most often')
mātūrē ('seasonably, betimes')	mātūrius ('more seasonably')	māturrimē ('most seasonably')
prope ('near')	propius ('nearer')	proximē ('nearest, next')
nūper ('recently')	—	nūperrimē ('most recently, previously')
potis ('possible')	potius ('rather')	potissimē ('especially')
—	prius ('before, previously')	prīmō ('first')
secus ('otherwise')	sētius sequius ('less')	—

Peculiarities within declension

Irregularity in number

Some nouns are only used in the singular (singulare tantum) such as:

• materials, such as aurum 'gold'

Some nouns are only used in the plural (plurale tantum), or when plural have a singular meaning such as:

• many festivals, such as Saturnālia 'Saturnalia'
• castra 'camp' and arma 'arms'; litterae 'a letter' (cf. littera 'letter of the alphabet')
• a few geographical names are plural such as Thēbae 'Thebes' (both the Greek and the Egyptian cities)

Indeclinable nouns

Indeclinable nouns are nouns which only have one form in all cases (of the singular).

• fās ('divine law')
• īnstar ('likeness')
• māne ('morning')
• nefās ('sin, abomination')
• secus ('(male or female) sex')

Heterogeneous nouns

Heterogeneous nouns are nouns which vary in respect to gender.

• A few nouns in the second declension occur in both the neuter and masculine. However, their meanings remain the same.
• Some nouns are one gender in the singular, but become another gender in the plural. They may also change in meaning.

Singular	Plural
balneum n. ('bath')	balneae f. or balnea n. ('bathhouse')
epulum n. ('feast, banquet')	epulae f. ('feast, banquet')
frēnum n. ('bridle, curb')	frēnī m. bridle, curb
iocus m. ('joke, jest')	ioca n. or ioci m. ('jokes, fun')
locus m. ('place, location')	loca n. ('region'); locī m. ('places in books, arguments')
rāstrum n. ('hoe, rake')	rāstrī m. ('hoes, rakes')

Plurals with alternative meanings

Singular	Plural
aedēs, aedis f. ('building, temple')	aedēs, aedium ('rooms, house')
auxilium, auxiliī n. ('help, aid')	auxilia, auxiliōrum ('auxiliary troops')
carcer, carceris m. ('prison, cell')	carcerēs, carcerum ('starting traps')
castrum, castrī n. ('fort, castle, fortress')	castra, castrōrum ('military camp, encampment')
cōpia, copiae f. ('plenty, much, abundance')	cōpiae, copiārum ('troops')
fortūna, fortūnae f. ('luck, chance')	fortūnae, fortūnārum ('wealth, fortune')
grātia, grātiae f. ('charm, favor')	grātiae, grātiārum ('thanks')
impedīmentum, impedīmentī m. ('impediment, hindrance')	impedīmenta, impedīmentōrum ('baggage, baggage train')
littera, litterae f. ('letter [alphabet]')	litterae, litterārum ('letter [message], epistle, scholarship, literature')
mōs, mōris m. ('habit, inclination')	mōrēs, mōrum m. ('morals, character')
opera, operae f. ('trouble, pains')	operae, operārum m. ('workmen')
*ops, opis f. ('help')	opēs, opium ('resources, wealth')
pars, partis f. ('part, piece')	partēs, partium ('office, function')

See also

• Declension of Greek nouns in Latin
• Latin conjugation
• Latin mnemonics
• William Whitaker's Words
• Greek declension

References

• Latin declensor (in Spanish)
• New Latin Grammar, an eBook, originally written by Charles Edwin Bennett, at the Project Gutenberg
• Interactive Latin Word Endings
• A Student's Latin Grammar, by Cambridge Latin Course's Robin m. Griffin, Third Edition
• Gildersleeve, B. L.; Gonzalez Lodge (1895). Gildersleeve's Latin Grammar (3rd ed.). Macmillan. ISBN 0-333-09215-5.
• Greenough, J. B.; G. L. Kittredge; A. A. Howard; Benj. L. D'Ooge (1903). Allen and Greenough's New Latin Grammar for Schools and Colleges. Ginn and Company.