#4th declension

[anacktoria-blog]

3rd/3rd-io and 4th Declension in Present Tense

To form the first and second declension, you simply cut off the -re at the end of the 2nd Principle Part (2PP) and add on the endings. For the 3rd/3rd-io and 4th declension, you must use a different technique. Think of them as a different set of endings - group 1 and 2 in your mind, and group 3 and 4 separately.

Under the cut I’ll explain how to form 3rd/3rd-io and 4th declensions in the present tense, and in both active and passive.

Active

Let’s take the verb lego, legere, legi, lectus (to read) as we work through how to form the 3rd declension.

Now, for present active, you always use the first principle part for singular 1st person. Therefore, “I read” will be lego. 1st Person, Singular, and Active will always be the 1st principle part. Now, I will explain how to get the other forms down.

For present tense, these are the steps we’ll use.

Cut off the -ere in the infinitive.

Add i (except in 3rd person plural - there, use u)

Add active endings

Note that instead of cutting off the -re, you cut off the vowel plus the -re on the end of the 2PP. Also note that for only 3rd person plural will the vowel will be u instead of i in the second step. You’ll notice the u will be present here in the 3rd-io and 4th declensions as well! So, let us form the verb lego for 2nd person singular.

Legere

Legi

Legis

Legis is our 2nd Person Singular Present form of lego! This means “you read.” Now, let’s do 3rd person plural so we can see how to use the u.

Legere

Legu

Legunt

The 3rd person plural is legunt! This means “they read.” Now, here is a chart of all of the present active forms of lego:

For 3rd-io and 4th, we use mostly the same steps, although the 4th declension already has the i when you cut off the -re. However, for simplicity, we will use the same steps, as the 3rd and 4th declensions are grouped together in how they are formed.

The only difference is that on the 3rd person plural, we use iu instead of just u.

4th declension forming: audio, audire, audivi, auditus (to hear).

Let’s do 1st person plural active:

audire

audi

audimus

Therefore, the 1st person plural active form of audio is audimus. Here is a chart of audio:

Passive

The ending for 1st person singular in passive is -or. However, the 3rd-io and 4th declensions will have an -i in front of the -or. So lego will become legor, but audio will become audior.

To make the other passive persons and numbers, we use the same steps, but with passive endings:

Cut off the -vowel re

Add i/u/iu

Add passive endings

For an example, here’s facio, facere, feci, factus (to make or do) in 3rd person singular

facere

faci

facitur

And so the passive present singular 1st person is facitur.

Here’s the chart for facio in passive present:

[realworldlatin]

"SCIENTIA POTENTATUS EST" "Knowledge is power" Potentatus, a nice masculine fourth declension noun, does mean "power". Making this technically correct. Potentatus, however, seems to be very uncommon in Classical Latin, appearing only once each in Cicero, Caesar, and Livy according to the Lewis and Short. A PHI Latin (latin.packhum.org) search only comes up with Caesar and Livy, plus an example from Justinian. Some of us might be more comfortable with the more popular "potentia", as in "Scientia potentia est." H/t to Thomas Schmid (@th_schmid) via Twitter for this found Latin.

[semperlapsuslinguae]

Fourth Declension

The fourth declension does not have many nouns.

Most are Masculine ending in -us

A few neuters end in -u

Masculine and Feminine

              Singular           Plural

Nom          us                  us Gen           us                  uum Dat            ui                   ibus Acc            um                 us Abl             u                    ibus

Example: metus, metus (Masculine) -fear, anxiety, dread

              Singular           Plural

Nom          metus            metus Gen           metus            metuum Dat            metui             metibus Acc            metum           metus Abl             metu              metibus

Neuter

              Singular            Plural

Nom           u                     ua Gen           us                    uum Dat             u                     ibus Acc             u                     ua Abl              u                     ibus

Example: cornu, cornus - horn

              Singular            Plural

Nom           cornu             cornua Gen            cornus           cornuum Dat             cornu             cornibus Acc             cornu             cornua Abl              cornu             cornibus

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Links to other declension posts:

1st declension

2nd declension

3rd declension

[kevinenglishlatinfinal-blog]

4th Declension Neuter

            Singular                                 Plural

Nom            u                                     ua 

Gen              us                                    uum

Dat           u                                         ibus

Acc             u                                       ua

Abl               u                                          ibus

[kevinenglishlatinfinal-blog]

4th Declension Masculine

         Singular                                 Plural

Nom            us                                     us 

Gen              us                                    uum

Dat           ui                                         ibus

Acc             um                                       ua

Abl               u                                          ibus