Classical Languages - Latin - Nouns - Fourth and Fifth Declensions

Fourth and Fifth Declensions, Irregular and Defective Nouns

Prerequisites: First and Second Declensions, Third Declension

This page completes the noun system. It treats the two small declensions, the fourth (stems in -u-) and the fifth (stems in -ē-), and then the nouns that do not follow the regular patterns: the mixed noun domus, the irregular nouns vīs, bōs, iter, senex, Iuppiter, and the defective nouns, which lack a number or some cases. The complete tables are in Paradigms: nouns.

Fourth declension

The fourth declension contains masculine and feminine nouns in -us and neuters in -ū. The genitive singular ends in -ūs and the dative singular in -uī.

Endings

	Singular (m., f.)	Plural (m., f.)	Singular (n.)	Plural (n.)
Nominative	-us	-ūs	-ū	-ua
Genitive	-ūs	-uum	-ūs	-uum
Dative	-uī	-ibus	-ū	-ibus
Accusative	-um	-ūs	-ū	-ua
Ablative	-ū	-ibus	-ū	-ibus
Vocative	-us	-ūs	-ū	-ua

Models

manus, manūs f. hand, band; exercitus, exercitūs m. army; cornū, cornūs n. horn, wing of an army.

Singular

	manus	exercitus	cornū
Nominative	manus	exercitus	cornū
Genitive	manūs	exercitūs	cornūs
Dative	manuī	exercituī	cornū
Accusative	manum	exercitum	cornū
Ablative	manū	exercitū	cornū
Vocative	manus	exercitus	cornū

Plural

	manus	exercitus	cornū
Nominative	manūs	exercitūs	cornua
Genitive	manuum	exercituum	cornuum
Dative	manibus	exercitibus	cornibus
Accusative	manūs	exercitūs	cornua
Ablative	manibus	exercitibus	cornibus
Vocative	manūs	exercitūs	cornua

Notes

Vowel length separates forms. manus (nominative and vocative singular, short u) differs from manūs (genitive singular, nominative, accusative and vocative plural, long ū). The accusative plural has the same form as the nominative plural.
The genitive decides the declension. A noun in -us belongs to the 2nd declension if the genitive is -ī (dominus, dominī) and to the 4th if it is -ūs (exercitus, exercitūs).
The dative singular is -uī in the masculine and feminine and -ū in the neuter. The masculine and feminine form is occasionally contracted to -ū.
Gender. Nouns in -us are masculine, with a few feminine exceptions: manus, domus, tribus, porticus, acus (needle), quercus (oak) and Īdūs (the Ides, plural). The neuters are cornū, genū (knee) and verū (spit).
Dative and ablative plural in -ubus. A few nouns keep -u- before -bus: tribus (tribubus), artus (limbs), lacus, arcus and specus. The ordinary ending is -ibus.
Many fourth declension nouns are verbal nouns: adventus (arrival, from adveniō), cantus (song), ūsus (use, from ūtor), senātus. The supine (hortātum, hortātū) is in origin the accusative and the ablative of a fourth declension verbal noun.

Spem vultū simulat, premit altum corde dolōrem.

He feigns hope in his face and keeps deep grief hidden in his heart. (Vergil, Aeneid 1.209; vultū is the ablative singular of vultus, vultūs, and spem the accusative of a 5th declension noun)

Per variōs cāsūs, per tot discrīmina rērum, tendimus in Latium.

Through various chances, through so many dangers, we make for Latium. (Vergil, Aeneid 1.204–205; cāsūs is the accusative plural of cāsus, cāsūs, rērum the genitive plural of rēs)

Core vocabulary

Nominative and genitive	Gender	Meaning
adventus, adventūs	m.	arrival
cāsus, cāsūs	m.	chance, misfortune, case
cornū, cornūs	n.	horn, wing of an army
currus, currūs	m.	chariot
equitātus, equitātūs	m.	cavalry
exercitus, exercitūs	m.	army
fructus, fructūs	m.	fruit, enjoyment
gradus, gradūs	m.	step, rank
impetus, impetūs	m.	attack
lacus, lacūs	m.	lake
manus, manūs	f.	hand, band
metus, metūs	m.	fear
portus, portūs	m.	harbour
senātus, senātūs	m.	senate
sēnsus, sēnsūs	m.	feeling, sense
spīritus, spīritūs	m.	breath, spirit
tribus, tribūs	f.	tribe
tumultus, tumultūs	m.	uproar
ūsus, ūsūs	m.	use, experience
vultus, vultūs	m.	face, expression

Fifth declension

The fifth declension is small. Its nouns end in -ēs, are feminine (with two exceptions) and have the genitive singular in -ēī or -eī.

Endings

	Singular	Plural
Nominative	-ēs	-ēs
Genitive	-ēī, -eī	-ērum
Dative	-ēī, -eī	-ēbus
Accusative	-em	-ēs
Ablative	-ē	-ēbus
Vocative	-ēs	-ēs

Models

rēs, reī f. thing, affair; diēs, diēī m. (f.) day.

	rēs sg.	rēs pl.	diēs sg.	diēs pl.
Nominative	rēs	rēs	diēs	diēs
Genitive	reī	rērum	diēī	diērum
Dative	reī	rēbus	diēī	diēbus
Accusative	rem	rēs	diem	diēs
Ablative	rē	rēbus	diē	diēbus
Vocative	rēs	rēs	diēs	diēs

Notes

Quantity of the genitive and dative singular. The e is long after a vowel (diēī, faciēī, speciēī) and short after a consonant (reī, speī, fideī).
Few plurals. Only rēs and diēs are declined in full in the plural. aciēs, speciēs, faciēs and spēs have a plural in the nominative and the accusative only, and most of the others have no plural.
Gender. All nouns of the 5th declension are feminine except diēs and merīdiēs (midday), which are masculine. diēs is masculine in the plural, and in the singular it is usually masculine but feminine when it means a fixed day or a span of time.
Phrases with rēs: rēs pūblica (the state), rēs gestae (deeds), rēs novae (revolution). The word has many meanings, and the context decides.

Sunt lacrimae rērum et mentem mortālia tangunt.

There are tears for things, and mortal sorrows touch the heart. (Vergil, Aeneid 1.462; the phrase lacrimae rērum is hard to translate, and the tears of things is one rendering)

Carpe diem, quam minimum crēdula posterō.

Seize the day, trusting as little as possible in the next. (Horace, Odes 1.11.8; diem is the accusative singular of diēs)

Core vocabulary

Nominative and genitive	Gender	Meaning
aciēs, aciēī	f.	battle line, edge
diēs, diēī	m. (f.)	day
faciēs, faciēī	f.	face, appearance
fidēs, fideī	f.	faith, trust
glaciēs, glaciēī	f.	ice
merīdiēs, merīdiēī	m.	midday
perniciēs, perniciēī	f.	destruction
rabiēs, rabiēī	f.	rage
rēs, reī	f.	thing, affair
speciēs, speciēī	f.	appearance, sight
spēs, speī	f.	hope
seriēs, seriēī	f.	row, sequence

Identifying the declension

The genitive singular is the surest guide:

Declension	Genitive singular	Usual nominative	Gender	Example
1st	-ae	-a	f. (a few m.)	rosa, rosae
2nd	-ī	-us, -er, -ir; -um	m.; n.	dominus, dominī; bellum, bellī
3rd	-is	various	m., f., n.	rēx, rēgis
4th	-ūs	-us; -ū	m. (f.); n.	manus, manūs; cornū, cornūs
5th	-ēī, -eī	-ēs	f. (diēs m.)	rēs, reī

Singular

	1st	2nd (m.)	3rd (m., f.)	4th (m., f.)	5th
Nominative	-a	-us	—	-us	-ēs
Genitive	-ae	-ī	-is	-ūs	-ēī, -eī
Dative	-ae	-ō	-ī	-uī	-ēī, -eī
Accusative	-am	-um	-em	-um	-em
Ablative	-ā	-ō	-e	-ū	-ē
Vocative	-a	-e	—	-us	-ēs

Plural

	1st	2nd (m.)	3rd (m., f.)	4th (m., f.)	5th
Nominative	-ae	-ī	-ēs	-ūs	-ēs
Genitive	-ārum	-ōrum	-um	-uum	-ērum
Dative	-īs	-īs	-ibus	-ibus	-ēbus
Accusative	-ās	-ōs	-ēs	-ūs	-ēs
Ablative	-īs	-īs	-ibus	-ibus	-ēbus
Vocative	-ae	-ī	-ēs	-ūs	-ēs

The dash in the 3rd declension means that the nominative and vocative singular have no common ending. A noun in -us may be 2nd or 4th, and the genitive decides.

domus, a noun of two declensions

domus, domūs f. house, home mixes the 4th and the 2nd declensions.

	Singular	Plural
Nominative	domus	domūs
Genitive	domūs, domī	domuum, domōrum
Dative	domuī, domō	domibus
Accusative	domum	domōs, domūs
Ablative	domō, domū	domibus
Vocative	domus	domūs
Locative	domī

The usual forms in classical prose are domūs (genitive), domuī or domō (dative), domō (ablative), domōs (accusative plural) and domōrum or domuum (genitive plural). The others are less frequent.
domus is feminine.
Three forms express place without a preposition: domī at home (locative), domum (to) home (accusative of the goal), domō from home (ablative of the source). They are treated on Accusative and Ablative and locative.

Example (constructed)	Translation
Domī manet.	He stays at home.
Domum redit.	He returns home.
Domō exit.	He goes out from home.

The phrase domī mīlitiaeque, at home and in the field, is a stock expression of Latin prose.

Irregular nouns

These nouns are frequent and deviate from the declension to which they belong.

vīs, bōs, iter, senex, Iuppiter

Singular

	vīs force	bōs ox, cow	iter journey	senex old man	Iuppiter
Nominative	vīs	bōs	iter	senex	Iuppiter
Genitive	vīs (rare)	bovis	itineris	senis	Iovis
Dative	vī (rare)	bovī	itinerī	senī	Iovī
Accusative	vim	bovem	iter	senem	Iovem
Ablative	vī	bove	itinere	sene	Iove
Vocative	vīs	bōs	iter	senex	Iuppiter

Plural

	vīs	bōs	iter	senex
Nominative	vīrēs	bovēs	itinera	senēs
Genitive	vīrium	boum	itinerum	senum
Dative	vīribus	būbus, bōbus	itineribus	senibus
Accusative	vīrēs	bovēs	itinera	senēs
Ablative	vīribus	būbus, bōbus	itineribus	senibus
Vocative	vīrēs	bovēs	itinera	senēs

vīs (f.) is a 3rd declension noun of an unusual shape. The singular has no regular genitive and dative, and the plural vīrēs has the stem vīr- and means strength, forces. It must not be confused with vir, virī (man, plural virī), nor with vīs the 2nd singular of volō.
bōs (m., f.) has the stem bov-. The genitive plural is boum and the dative and ablative plural būbus or bōbus.
iter (n.) has a nominative from one stem and all the other cases from itiner-: itineris, not iteris.
senex (m.) has the stem sen- in the other cases. The genitive plural is senum.
Iuppiter (m.) is a compound of an old vocative and pater; the other cases are made from the stem Iov-. It has no plural, and the vocative is the same as the nominative.

Vīs cōnsilī expers mōle ruit suā.

Force without judgement falls by its own weight. (Horace, Odes 3.4.65)

Multa senem circumveniunt incommoda.

Many troubles surround an old man. (Horace, Ars Poetica 169)

Ab Iove prīncipium, Mūsae: Iovis omnia plēna.

From Jupiter let us begin, Muses; all things are full of Jupiter. (Vergil, Eclogues 3.60)

Example (constructed)	Translation
Mīlitēs vīribus carēbant.	The soldiers lacked strength.
Bovēs ex agrō domum dūcuntur.	The oxen are led home from the field.
Itinere fessī sunt.	They were tired from the journey.
Senex domī mansit.	The old man stayed at home.

Defective nouns

A defective noun lacks a number or some cases. There are several kinds.

Plural only

Noun	Meaning
arma, armōrum n.	arms
castra, castrōrum n.	camp
moenia, moenium n.	city walls
liberī, liberōrum m.	children
māiōrēs, māiōrum m.	ancestors
angustiae, angustiārum f.	narrow pass, difficulties
dīvitiae, dīvitiārum f.	riches
īnsidiae, īnsidiārum f.	ambush
nūptiae, nūptiārum f.	wedding
tenebrae, tenebrārum f.	darkness
Īdūs, Īduum f.	the Ides
Athēnae, Athēnārum f.	Athens

The plural form has a singular meaning in castra (a camp), Athēnae and nūptiae, and the adjective is plural.

Arma virumque canō.

I sing of arms and the man. (Vergil, Aeneid 1.1)

... altae moenia Rōmae.

... the walls of lofty Rome. (Vergil, Aeneid 1.7)

Singular only

Mass nouns and many abstract nouns have no plural: aurum (gold), argentum (silver), sāl (salt), pāx (peace), iūstitia, pulvis (dust), humus (ground), sōl (sun). When an abstract noun does form a plural, it usually means separate instances or kinds: virtūs (courage), virtūtēs (acts or kinds of courage).

Different meaning in the plural

Singular	Plural
aedēs, aedis f. temple	aedēs, aedium house
auxilium n. help	auxilia auxiliary troops
carcer m. prison	carcerēs starting gates
castrum n. fort	castra camp
cōpia f. supply, abundance	cōpiae troops, resources
fīnis m. end, limit	fīnēs territory
grātia f. favour	grātiae thanks
impedīmentum n. hindrance	impedīmenta baggage
littera f. letter of the alphabet	litterae a letter (epistle), literature
mōs, mōris m. custom	mōrēs character, morals
ops, opis f. power, help	opēs wealth, resources
rōstrum n. beak	rōstra the speakers' platform

Ō tempora, ō mōrēs!

What times, what customs! (Cicero, First Catilinarian 1.2; here mōrēs is the plural of mōs in the sense customs, morals)

locus has two plurals with different meanings: loca (places) and locī (passages in a book, topics); see First and second declensions.

Lacking some cases

Noun	Forms found	Meaning
fors f.	nominative fors, ablative forte	chance; forte by chance
prex f.	no nominative singular; precem, prece; plural precēs, precum, precibus	prayer
vicis f.	vicis, vicem, vice; plural vicēs, vicibus	change, turn
iussū m.	ablative only	by order
nātū m.	ablative only	by birth, in age (māior nātū, older)
fās, nefās n.	indeclinable	right, wrong
nihil n.	nominative and accusative nihil; the other cases from nūlla rēs	nothing

Ībam forte Viā Sacrā, sīcut meus est mōs.

I was walking by chance along the Sacred Way, as is my habit. (Horace, Satires 1.9.1)

Parsing practice

Give the case and number (all possibilities) and the dictionary entry.

manūs
manuī
exercituum
cornibus
rēs
rērum
diēī
spem
domī
domum
vīribus
bovem
itineris
Iovis
castrōrum

Answers

Genitive singular, or nominative, accusative or vocative plural, of manus, manūs f. (hand).
Dative singular of manus.
Genitive plural of exercitus, exercitūs m. (army).
Dative or ablative plural of cornū, cornūs n. (horn).
Nominative or vocative singular, or nominative, accusative or vocative plural, of rēs, reī f. (thing).
Genitive plural of rēs.
Genitive or dative singular of diēs, diēī m. (f.) (day).
Accusative singular of spēs, speī f. (hope).
Locative (at home) or genitive singular of domus, domūs f.
Accusative singular of domus (to home when it expresses the goal).
Dative or ablative plural of vīs, vīs f. (strength).
Accusative singular of bōs, bovis m., f. (ox).
Genitive singular of iter, itineris n. (journey).
Genitive singular of Iuppiter, Iovis m.
Genitive plural of castra, castrōrum n. pl. (camp).

Common pitfalls

Confusing manus and manūs. The length of the u separates the nominative singular from the genitive singular and the plural.
Writing -ī for the dative of the 4th declension. The dative is exercituī; exercitī belongs to the 2nd declension.
Treating manus and domus as masculine because of the ending. Both are feminine.
Forgetting that cornū is a neuter in the plural (cornua) and in the dative and ablative plural (cornibus).
Confusing the quantity of the 5th declension genitive. It is diēī with a long ē and reī with a short e.
Expecting a plural for every 5th declension noun. Only rēs and diēs have a full plural.
Mixing the forms of domus. The usual forms are domī (locative), domum (accusative) and domō (ablative), and the genitive is domūs.
Confusing vīrēs with virī. vīrēs is the plural of vīs (strength) and virī the plural of vir (men).
Writing bovibus for the dative plural of bōs. The forms are būbus or bōbus.
Declining iter from its nominative. The stem is itiner-: itineris.
Giving Iuppiter a plural. It does not have one.
Translating a plural-only noun with a plural meaning. castra is a camp, and litterae can be a single letter (epistle).
Taking the nominative to tell the declension. The ending -us can be 2nd or 4th declension, and the genitive decides.

Self-test

Give the genitive singular endings of the five declensions.
Decline exercitus in the plural and cornū in the singular.
Give the genitive singular and the gender of manus, domus, diēs, cornū, fidēs, tribus.
How do you say at home, to home and from home?
Translate: Dux exercitum ad portum dūxit. Rēs pūblica in perīculō est. Senex domī mansit. Bovēs ex agrō domum dūcuntur. Mīlitēs vīribus carēbant. Itinere fessī sunt.
What is the plural of vīs, what does it mean, and how does it differ from virī?
Give the genitive plural and the dative plural of bōs.
What do castra, cōpiae, litterae and mōrēs mean in the plural, and how do these differ from the singular?
Why is exercitī not a form of exercitus?
Decline Iuppiter. Why is there no plural?

Answers

1st -ae; 2nd -ī; 3rd -is; 4th -ūs; 5th -ēī or -eī.
exercitūs, exercituum, exercitibus, exercitūs, exercitibus (and the vocative exercitūs); cornū, cornūs, cornū, cornū, cornū (and the vocative cornū).
manūs f.; domūs f.; diēī m. (f.); cornūs n.; fideī f.; tribūs f.
domī; domum; domō.
The general led the army to the harbour. The state is in danger. The old man stayed at home. The oxen are led home from the field. The soldiers lacked strength. They were tired from the journey.
vīrēs, strength, forces. virī is the plural of vir, man.
boum; būbus or bōbus.
castra camp (singular castrum fort); cōpiae troops (singular cōpia supply); litterae letter (epistle), literature (singular littera letter of the alphabet); mōrēs character, morals (singular mōs custom).
exercitī is the genitive singular or the nominative plural of a 2nd declension noun; the 4th declension genitive is exercitūs.
Iuppiter, Iovis, Iovī, Iovem, Iove, vocative Iuppiter. The name of a single god has no plural.

Next: Adjectives

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