Showing posts with label declensions: 4th. Show all posts
Showing posts with label declensions: 4th. Show all posts

Friday, August 22, 2025

21.11.25: Level 1; Carolus et Maria [16][v] Grammar Notes (1): 4th declension nouns

There are four new nouns introduced in this text, all of which end in -us, but they belong to different declensions.

arcus: bow

carrus: wagon; cart

locus: place

manus: hand

Until now you have seen that nouns ending in -us are 2nd declension, and almost all of them are masculine. However, as mentioned in earlier posts, there are other nouns ending in -us that are not 2nd declension. How can you tell the difference? The answer is – if you only look at the nouns in the way they are listed above – you can’t, which is why it is important to note the nominative and genitive singular of a Latin noun, because the genitive singular is different for each declension i.e. it is the genitive singular that will tell you the declension.

[i] carrus and locus are second declension and are listed as follows:

carrus, -ī (gen. sg. in -ī) [2/m]

locus, -ī (gen. sg. -ī) [2/m]

[ii] arcus and manus are fourth declension and are listed as follows:

arcus, -ūs (gen. sg. in -ūs) [4/m] i.e. the only distinction between the nominative and genitive singular is the vowel length (nom. sg -us; gen. sg. -ūs)

Almost all 4th declension nouns in -us are masculine, but there are exceptions:

manus, -ūs (gen. sg. in -ūs) [4/f]

Some 4th declension nouns are neuter and end in a distinctive -ū in the nominative, for example:

cornū, -ūs (gen. sg. in -ūs) [4/n]: horn

LINK to all previous posts on the 4th declension:

https://mega.nz/file/DA9mFBBY#Yj4KLIjYqE17OtRVQkSaJZqDv6jNyOnfZjGSaIPUsc0


Thursday, December 5, 2024

05.03.25: Review of 4th declension nouns [3]; links to previous posts on the 4th declension

13.04.24: P.T. Barnum’s greatest show on earth

https://www.facebook.com/groups/latinforstarters/permalink/423701170241157/

13.04.24: the greatest 4th declension noun on earth!

https://www.facebook.com/groups/latinforstarters/permalink/423860346891906/

https://adckl.blogspot.com/2024/05/130424-greatest-4th-declension-noun-on.html

13.04.24: the greatest abbreviation in Rome

https://www.facebook.com/groups/latinforstarters/permalink/423701870241087/

https://adckl.blogspot.com/2024/05/130424-greatest-abbreviation-in-rome.html

13.04.24: 4th declension; vocabulary [1] - “exploring” vocabulary

https://www.facebook.com/groups/latinforstarters/permalink/423862540225020/

https://adckl.blogspot.com/2024/05/130424-4th-declension-vocabulary-1.html

13.04.24: 4th declension; vocabulary [2]

https://www.facebook.com/groups/latinforstarters/permalink/423865213558086/

https://adckl.blogspot.com/2024/05/130424-4th-declension-vocabulary-2.html

13.04.24: 4th declension; vocabulary [3]

https://www.facebook.com/groups/latinforstarters/permalink/423870953557512/

https://adckl.blogspot.com/2024/05/130424-4th-declension-vocabulary-3.html

13.04.24: 4th declension nouns; vocabulary [4]

https://www.facebook.com/groups/latinforstarters/permalink/423871433557464/

https://adckl.blogspot.com/2024/05/130424-4th-declension-nouns-vocabulary-4.html

13.04.24: 4th declension nouns; vocabulary [5] military

https://www.facebook.com/groups/latinforstarters/permalink/423873760223898/

https://adckl.blogspot.com/2024/05/130424-4th-declension-nouns-vocabulary.html

13.04.24: 4th declension nouns; vocabulary [6]

https://www.facebook.com/groups/latinforstarters/permalink/423874973557110/

https://adckl.blogspot.com/2024/05/130424-4th-declension-nouns-vocabulary-6.html

13.04.24: 4th declension nouns; derivatives and borrowings

https://www.facebook.com/groups/latinforstarters/permalink/423882426889698/

https://adckl.blogspot.com/2024/05/130424-4th-declension-nouns-derivatives.html

13.04.24: domus

https://www.facebook.com/groups/latinforstarters/permalink/423891043555503/

https://adckl.blogspot.com/2024/05/130424-domus.html

13.04.24: practice for the 4th declension [1]

https://www.facebook.com/groups/latinforstarters/permalink/424215126856428/

https://adckl.blogspot.com/2024/05/130424-practice-for-4th-declension-1.html

13.04.24: practice for the 4th declension [2]

https://www.facebook.com/groups/latinforstarters/permalink/424216323522975/

https://adckl.blogspot.com/2024/05/130424-practice-for-4th-declension-2.html

13.04.24: Schoolbook sentences [2]

https://www.facebook.com/groups/latinforstarters/permalink/424218646856076/

https://adckl.blogspot.com/2024/05/130424-schoolbook-sentences-2.html

13.04.24: Examples of 4th declension nouns in context

https://www.facebook.com/groups/latinforstarters/permalink/424219933522614/

https://adckl.blogspot.com/2024/05/130424-examples-of-4th-declension-nouns.html

14.04.24: reading the 4th declension

https://www.facebook.com/groups/latinforstarters/permalink/424498983494709/

https://adckl.blogspot.com/2024/05/140424-reading-4th-declension.html

All links in one file:

https://mega.nz/file/yYUXRBhK#kfN8vj3w1jkEPLTM-GftWkSz6Iz55BnGau2J0hXMPek

05.03.25: review of 4th declension nouns [2]

Label the images

adventus, -ūs [4/m]

exercitus, -ūs [4/m]

impetus, -ūs [4/m]

lacus, -ūs [4/m]

magistrātus, -ūs [4/m]

reditus, -ūs [4/m]

manus, -ūs [4/f]

cornu, -ūs [4/n]

genu, -ūs [4/n] 

05.03.25: Review of 4th declension nouns [1]

Identify the seven 4th declension nouns; they have all appeared in the recent texts. If you’re not sure, the only way you can identify them is by the genitive singular in -ūs which will be listed in vocabularies and dictionaries.

adventus

exercitus

hortus

impetus

iūs

lacus

locus

magistrātus

manus

mūs

pectus

pondus

reditus

vellus

Wednesday, August 7, 2024

08.09.24: Follow-up [4]; 4th declension; accusative case

Referring to Vincent’s video:

https://adckl.blogspot.com/2024/08/080924-quid-in-caelo-videre-potes-1.html

[4] 4th declension

Here are the group links to posts on the 4th and 5th declension

https://www.facebook.com/.../permalink/470682685543005/

Nominative: arcus pluvius > accusative: Arcum pluvium in caelō videō. │ I see a rainbow in the sky.

Nominative: tonitrus > accusative: Tonitrum in caelō audiō. │ I hear thunder in the sky.

Nominative plural: Duo arcūs pluviī in caelō sunt. │ There are two rainbows in the sky.

> Accusative plural: Duōs arcūs pluviōs in caelō videō. │ I see two rainbows in the sky.

What this topic also shows is that Latin nouns can have the same ending but belong to different declensions:

2nd declension: corvus (crow)

3rd declension: sidus (star; constellation)

4th declension: tonitrus (thunder)

Level 1: learn the meanings of the word

Moving on …

There is no way of knowing what declension they belong to if you only know the nominative of the word. However, all the genitive singular forms of the nouns are different which is why, when thoroughly learning Latin nouns, you need to know both the nominative and genitive singular because that will give you the declension; dictionaries and textbooks will always list the nouns that way. That is particularly crucial with 3rd declension nouns because they often undergo a change in the genitive singular which applies to all endings added to the word:

2nd declension

corvus [nominative singular], corvī [genitive singular]; abbreviated to corvus, -ī [2/m]

3rd declension

sidus, sideris [3/n] > Siderin caelō videō.

4th declension

tonitrus, tonitrūs; abbreviated to tonitrus, -ūs [4/m]



Saturday, May 4, 2024

14.04.24: reading the 4th declension

Read the text for understanding; don’t be concerned by any word or phrase you don’t know. We’ll look at the text a second time in the next post.

The first purpose of this text is to see 4th declension nouns in context.

Look at the cases of the nouns in bold and see how they are being used. Then try the exercise that follows the text.

DĒ EXERCITIBUS RŌMĀNĪS I

[Chesnutt: Road to Latin]

equitātus, -ūs [4/m]: cavalry

exercitus, -ūs [4/m]: army

impetus, -ūs [4/m]: attack

ūsus, -ūs [4/m]: use; service

cornū, -ūs [4/n]: (here) wing (of an army)

Exercitus Rōmānus, quem Caesar in Galliam dūcēbat, in trēs partēs dīvīsus est. Ūna pars exercitūs equitātus erat, altera pars auxilia, tertia pars peditēs, quī mīlitēs legiōnāriī appellābantur.

Potentissima pars exercitūs Rōmānī erant legiōnēs, nam habēbant mīlitēs legiōnāriōs, virōs maximae virtūtis, quī pīlīs gladiīsque pugnābant. Ubi Caesar signum dedit [gave], mīlitēs prīmī in hostēs appropinquantēs pīla mittēbant; tum gladiīs in eōs impetum faciēbant. Post proelium equitātus, quī in cornū dextrō et in cornū sinistrō cōnstiterat [had halted], in hostēs fugientēs impetum faciēbat et eōs caedēbat. Ante proelium quoque equitātus Caesarī et exercituī magnō auxiliō erat, nam equitātus cum equitātū hostium proelium saepe committēbant. Auxilia, vel peditēs levis armātūrae, proeliīs nōn saepe pugnābant. Eae cōpiae tamen magnō ūsuī erant, quod ad exercitum frūmentum ā fīnitimīs gentibus coāctum portābant. Ab exercitū Caesaris multae gentēs victae sunt; nam mīlitēs Rōmānī virtūte vīribusque omnēs aliōs superāvērunt [overcame].

Exercitūs Rōmānī ad multās terrās sociīs praesidiō mittēbantur. Mīlitēs eōrum exercituum terrā marīque pugnābant. Nūllī exercitūs exercitibus Rōmānīs parēs erant virtūte. Omnēs nātiōnēs orbis terrārum igitur potentēs exercitūs Rōmānōs timēbant. Diū cum Rōmānīs bellum gerēbant, sed frūstrā pugnābant, nam omnēs nātiōnēs ab exercitibus Rōmānīs victae sunt.

Below are English translations of phrases from the text: find the sentences and phrases and note in particular the 4th declension nouns and how they are working. They aren’t in order; they’re listed according to cases.

1. The Roman army [nominative] … was divided into three parts

2. Roman armies [nominative plural] were often sent to many lands

3. The most powerful part ¦ of the Roman army [genitive] ¦ were the legions

4. The soldiers ¦ of their armies [genitive plural] ¦ would fight on land and at sea

5. One part ¦ of the army [genitive] ¦ was ¦ the cavalry [nominative]

6. Before the battle the cavalry was of great assistance to Caesar and to the army [dative]

7. These troops were ¦ of great use [dative; a note on this will be given in the next post]

8. No armies [nominative plural] were ¦ equal to the Roman armies [dative plural] ¦ in courage

9. Then they would make an attack [accusative] on them with swords

10. They carried grain ¦ to the army [accusative with preposition]

11. They feared the powerful Roman armies [accusative plural]

12. on the right wing [ablative]

13. on the left wing [ablative]

14. Many nations were conquered ¦ by Caesar’s army [ablative]

15. All the nations were conquered ¦ by the Roman armies [ablative plural]

16. for ¦ the cavalry [nominative] ¦ would often commence battle ¦ with the cavalry [ablative] ¦ of the enemy

13.04.24: Examples of 4th declension nouns in context

[1] Caesar, referring to the back of a hill:

sed hunc silvestrem et angustum, quā esset aditus [nominative] ad alteram partem oppidī ¦ but likewise woody and narrow, by which there was a pass to the other side of the town

[2] In nōmine patris, fīliī et spīritūs [genitive] sānctī ¦ in the name of the father, [of] the son and [of] the holy spirit

[3] Caesar, concerning the Druids:

Magnum ibi numerum versuum [genitive plural] ēdiscere dīcuntur. ¦ They are said there to learn by heart a great number ¦ of verses

[4] Celsus, on Medicine:

cāsus, -ūs [4/m]: fall; accident; misfortune > ME: case

siquidem etiam in hōc cāsū [ablative] quaedam similitūdō est femōrī et umerō … pedī et manuī ¦ for in this (kind of) accident also there is some similarity to the thigh and upper arm … (to) the foot and (tothe hand [dative]

[5] deinde Pānsa et Hirtius, quī quasi cornu[accusative plural] duo tenuērunt Caesaris (Cicero) ¦ and next to him Pansa and Hirtius, who held (if I may use such an expression) the two horns of Caesar

[6] Audīrēs ululātūs [accusative plural] fēminārum, infantium quirītātūs [accusative plural] (Pliny) ¦ You could hear the howlof women, the screamof children

[7] Iussū [ablative] Imperātōris ¦ pompa magnifica tōtam per urbem dūcēbātur. ¦ At the emperor's order [= on the order ¦ of the emperor], a splendid procession was being led through the whole city.

[8] Cēnāvīn ego heri in nāvī in portū [ablative] Persicō? (Plautus) ¦ Did I not dine yesterday on board ship in the Persian Port?

[9] Habet autem in manū [ablative] sinistrā stēllās quattuor (Hyginus) ¦ However, he has four stars in his left hand

[10] plōrātus, -ūs [4/m]: wailing

plōrātus [nominative] mulierum nōn ex prīvātīs sōlum domibus [ablative plural] exaudiēbātur (Livy) ¦ the wailing of women was heard not only from private houses

13.04.24: practice for the 4th declension [2]: schoolbook sentences [1]

We sometimes laugh at old schoolbooks and the “useless sentences” which they often provide. However, to mock them is to misunderstand their purpose. Some of these dry old schoolmasters knew exactly what they were doing; some of them at least already knew that confronting pupils with endless tables wasn’t working; in fact it was intimidating. That’s why, when I’ve posted the tables, they have been for reference, and so you can pick up the endings slowly. This post and the next one focus on exercises from a “dusty” old schoolbook published in 1880. The sentences are short, they each focus on a particular case and particular case use. All of them are giving practice in the 4th declension. This time, I’ll give translations and mention again the function of each case. In the second post, you’re on your own. 

clādēs, clādis [3/f]: defeat

sonitus, -ūs [4/m]: sound

singular

[1] nominative

Vultus [nominative: the subject of the sentence] iūdicis sevērus est. The face of the judge (the judge's face) is stern.

Mātris vultus [nominative: the subject of the sentence] benignus est. The face of the mother (the mother's face) is kind.

Domus [nominative: the subject of the sentence] hominibus est cāra. The house is dear to people (people like the house)

[2] genitive

Scūta peditātūs [genitive: possession; of] parva sunt. The shields of the infantry are small.

Clādēs equitātūs [genitive: possession; of] est magna. The defeat of the cavalry is great.

[3] dative

Dux exercit [dative: indirect object] est cārus. The commander is dear to the army.

[4] accusative

Nautae portum [accusative: direct object] dēfendunt. The ships defend the port.

Dux equitātum [accusative: direct object] laudat. The commander praises the army.

[5] ablative

Nāvēs in portū sunt. [ablative: with the preposition in]. The ships are in the port.

Gladius est in ducis manū. [ablative: with the preposition in]. The sword is in the hand of the commander.

Plural

[1] nominative

Flūctūs maris [nominative plural: subject] altī sunt. The waves of the sea are high.

[2] genitive

Sonitus flūctuum [genitive plural: possession; of] grātus est. The sound of the waves is pleasing.

Numerus portuum [genitive plural: possession; of] magnus est. There is a great number of ports.

[3] dative

Nūllī exercitūs exercitibus [dative plural; indirect object; to] Rōmānīs parēs erant virtūte. No armies were equal to the Roman armies in courage.

[4] accusative

Ītalia multōs portūs [accusative plural: direct object] habet. Italy has many ports.

Rēgīna albās manūs [accusative plural: direct object] habet. The queen has white hands.

Mīlitēs longōs arcūs [accusative plural: direct object] habent. The soldiers have long bows.

[5] ablative

Omnēs nāvēs ē portibus [ablative plural: with preposition ē / ex] Ītaliae exeunt. All the ships depart from the ports of Italy.

Yes, you’ll probably never need to say “The queen has white hands” but it isn’t a question of the importance of the meaning, but the importance of the grammar that’s being used. In fact, sometimes the odder the meaning, the more memorable the sentence is.

Two Youtube links explaining the 4th declension:


13.04.24: practice for the 4th declension [1]

What cases are these 4th declension nouns in? Although the tables were posted earlier, I will attach them here again. Some of them can refer to more than one case and so keep a close eye on the endings.

tonitrus, -ūs [4/m]: thunder

  1. arcū
  2. cornuum
  3. domī
  4. domuum
  5. exercitus
  6. exercitūs
  7. fructūs
  8. genuī
  9. impetus
  10. manibus
  11. pecua
  12. portuī
  13. senātuī
  14. tonitrū
  15. vultum

13.04.24: domus

The question “What do you identify as?” has become commonplace – and a cause of some controversy. Well, below is a noun that has had problems with self-identification for thousands of years!

Domus [f] (house) needs careful study because it has a mixture of second (indicated in green) and fourth (indicated in yellow) declension endings.

However, 99.999% of Latin nouns do know what they are. It's domus that stands out from the crowd.

13.04.24: 4th declension nouns; derivatives and borrowings

When I was writing about 3rd declension nouns, I explained that knowing English derivatives can go – quite far – in showing you how they work.

You can do something similar with 4th declension nouns. Many of them end up in English either as derivatives or borrowings with the original -us ending missing.

corn: not the food [that’s of Germanic origin], but the condition from which people’s feet can be affected

Modern English (ME): corn < Old French: corn < Latin: cornū (horn)

The grammatical ending in Latin is lost in Old French before it ends up in English.

And there is a pattern to this in the derivatives and borrowings:

ME: aqueduct; MFr: aqueduc < Latin: aquaeductus

ME: audit < Latin: audītus

ME: course < Old French: cours < Latin: cursus

ME: fig < Old French: figue < Latin: fīcus

ME: lake < Old French: lac < Latin: lacus

ME: magistrate < Latin: magistrātus

ME: pace < Old French: pas < Latin: passus

ME: port < Anglo-Saxon: port, borrowed from Latin: portus

ME: senate < Latin: senātus

ME: sense < Old French: sen(s) < Latin: sēnsus

ME: spirit < Old French: espirit < Latin: spīritus

ME: use < Old French: us < Latin: ūsus

ME: verse < Old French: vers < Latin: versus

However, it is not guaranteed that an English derivative displaying this feature is a 4th declension noun:

ME: pork < Old French: porc < Latin: porcus [2nd declension] pig

ME: angle < Latin: angulus [2nd declension] corner

And posted is a favourite of mine! Part of a Roman fresco depicting a basket of figs: fīcus.

13.04.24: 4th declension nouns; vocabulary [6]

The endings -sus and -tus can sometimes mark a fourth declension noun. These nouns are derived from verbs.

spīro, spīrāre [1]: breath > spīritus: breath; spirit

sentiō, sentīre [4]: feel > sēnsus: feeling; sense; sensation

A number of 4th declension nouns are derived from verbs of movement [image #1]

The next time you’re bored to death in transit in an airport, or you’re looking for an exit sign, or you’re looking forward to Christmas and have given the kids an advent calendar, you’re dealing with 4th declension nouns! [image #2]


13.04.24: 4th declension nouns; vocabulary [5] military

One way of learning vocabulary is to group words together which have a connected theme, for example the five senses. A number of 4th declension words connected with the military and military tactics can be grouped together:

arcus, -ūs [4/m]: bow; arcus pluvius: rainbow

currus, -ūs [4/m]: chariot*

equitātus, -ūs [4/m]: cavalry

exercitus, -ūs [4/m]: army

impetus, -ūs [4/m]: attack

iussus, -ūs [4/m]: command

peditātus, -ūs [4/m]: infantry; foot-soldiers

cornū, -ūs [4/n]: wing

*Chariots were used in ancient battles but were superseded by cavalry since chariots pulled by more than one horse were not as easy to control as a single mounted horse. When stronger horses were bred, they could be ridden. Chariots were difficult to manoeuvre over rough terrain, a cavalry force more able to engage in complex manoeuvres. War chariots had to be pulled by more than one horse. Therefore, a cavalry comprising single mounted horses allowed for more cavalry to be fielded than chariots. And if one of the horses pulling a chariot was injured or killed, the chariot itself became useless.



13.04.24: 4th declension nouns; vocabulary [4]

cornū, -ūs [4/n]: one word with several meanings

13.04.24: 4th declension; vocabulary [3]

quinque sēnsūs

Latin expresses the five senses (sēnsus, -ūs [4/m] ) using 4th declension nouns:

audītus, -ūs [4/m]: hearing

gustus, -ūs [4/m]: taste

odōrātus, -ūs [4/m]: smell

tāctus, -ūs [4/m]: touch

vīsus, -ūs [4/m]: sight

13.04.24: 4th declension; vocabulary [2]

Some words have historical connections or specific meanings pertaining to Ancient Rome, or there are memorable examples of them in the literature.

Idūs [4/f] (plural only): the ides; in the Roman calendar the fifteenth day of March, May, July, October, and the thirteenth day of the other months.

“Beware the Ides of March” was the Soothsayer’s warning to Julius Caesar in Shakespeare’s play. If it was actually said, Caesar paid no attention, because on the Ides of March 44BC he was stabbed to death in the Theatre of Pompey by as many as 60 conspirators including his associates Brutus and Cassius.

There may never have been a soothsayer, but there is no doubt that Caesar was assassinated on March 15th since a commemorative coin was issued by Brutus two years later.

The words EID MAR are abbreviations for EIDIBVS MARTIIS ‘on the Ides of March’ and the coin has representations of the weapons used by Brutus and Cassius in addition to an image of a pil(l)eus, a felt cap given to freed slaves, and symbolic of the liberty won through the death of Caesar.

And ULUlātus, -ūs [4/m] is an example of an onomatopoetic word ie. one that reflects the sound being made, here ‘hOWLing’



13.04.24: 4th declension; vocabulary [1] - “exploring” vocabulary

When you’re working with kids, you have to devise a whole range of methods to help them learn vocabulary: word searches, crosswords, match the word with the image, unscramble the letters, fill in the gaps etc. Another way is simply to “talk” about the words, give some additional, hopefully, interesting piece of information or show how it’s found its way into English. So, over the next few posts, I’ll give some information about a few of these 4th declension nouns which, I hope, will be a bit more interesting than staring at a list of words on a piece of A4. Also, by “exploring” them, you realise that they aren’t all as alien as they may first appear.

And, with reference to an earlier post, you may well remember that 4th declension noun ēgressus (exit) simply by its association with P.T. Barnum.

We’ll begin with a few words which have been adopted into English, and a few which have English derivatives.


13.04.24: the greatest abbreviation in Rome

And another one as a way in …

The most famous abbreviation in Ancient Rome

First used on inscriptions during the late republic in 80BC, its last appearance being on coins during the reign of Constantine (312-337AD), the abbreviation SPQR stands for:

SENĀTUS POPULUSQUE RŌMĀNUS

The Roman Senate and People refers to the government of Rome, the absence of monarchy (there had been no king since 509BC after the overthrow of Lucius Tarquinius Superbus) and the importance of the Roman people themselves in the running of the state.

But here’s the question:

senātus: senate

populus: people

Both end in -us, and so both are 2nd declension?

See the next post

13.04.24: the greatest 4th declension noun on earth!

As a way into the next topic …

Welcome to P.T. Barnum’s Greatest Show on Earth. The visitors packed the museum and would have been fascinated to see the “egress” … but what did they see? Yes, the “Greatest Showman” used a bit of Latin to hoodwink them!


Visitors to P.T. Barnum’s museum would stay there all day. This affected the profits because they couldn’t take in more visitors. In true Barnum style, he hit on the idea of a sign pointing to the egress. Of course, people headed for that attraction, not knowing that egress is another word for ‘exit’ from Latin, ēgressus, a fourth declension noun.

And we’ll move from Barnum to an argument …

in nomine patris, filiī et spiritūs sanctī

in the name ¦ of the father ¦ (and) of the son and ¦ of the holy spirit

This caused a mini civil war in another FB group where one member insisted that spiritūs was wrong, that it should be spiritī because spiritus, since it ends in -us, is second declension.

The member was not correct; spiritūs is right. Spiritus is a fourth declension noun. But I can see why he thought the way he did.

Regardless of your beliefs, the above phrase is handy to know because it shows you three declensions in the one phrase:

  • fīlius, genitive singular filiī: 2nd declension [-ī]
  • pater, genitive singular patris: 3rd declension [-is]
  • spiritus, genitive singuar spiritūs: 4th declension [-ūs]

Those genitive singular endings are crucial because they absolutely mark the declension to which a noun belongs:

  • -ī [2nd declension]
  • -is [3rd declension]

and, the new one:

  • -ūs with long /ū/ [4th declension]

Compare these three:

populus (people), opus (work), senātus (senate).

There is no way of working out to which declension these three belong unless you learn the word along with its genitive singular. That will always tell you the declension.

  • populus, -ī [2nd declension]
  • opus, operis [3rd declension]
  • senātus, senātūs [4th declension]

In Classical Latin writing no macron was used, and so both the nominative and genitive look the same, but are pronounced differently. Most edited texts, and schoolbooks will use the macron to avoid confusion in meaning, and so it’s useful to keep it there: senātus [nominative], senātūs [genitive]

So, in SENĀTUS POPULUSQUE RŌMĀNUS, senātus is 4thdeclension, and populus is 2nd declension.

4th declension nouns are far fewer in number than the other massive groups of the 1st, 2nd and 3rd declension; they were all covered in earlier posts. Nevertheless, there are some nouns which commonly occur in the literature. Most 4th declension nouns are masculine; if any are feminine, they have the same endings. [image #1]

cursus, -ūs [4/m]: running; race; career

flūctus, -ūs [4/m]: wave

frūctus, -ūs [4/m]: fruit

gradus, -ūs [4/m]: step; stair

habitus, -ūs [4/m]: character; habit; dress; attire

lacus, -ūs [4/m]: lake

manus, -ūs [4/f]: hand

metus -ūs [4/m]: fear

questus, -ūs [4/m]: complaint

spīritus, -ūs [4/m]: air; breath; breathing; spirit

ululātus, -ūs [4/m]: wailing

ūsus, -ūs [4/m]: use; habit

vultus, -ūs [4/m]: face; facial expression

There are few neuter nouns of the fourth declension [genū, -ūs 4/n: knee; pecū, -ūs 4/n: cattle]; they are distinguishable from masculine and feminine nouns by having  in the nominative singular. [image #2]

cornū, -ūs [4/n]: horn

genū, -ūs [4/n]: knee

pecū, -ūs [4/n]: cattle

The tables are posted for reference but, over the next few posts, I'll talk about some of the useful vocabulary that's in the 4th declension.