Lesson 11. Of Nouns: Third Declension

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We now move forward to the Third Declension of nouns. This is a good moment to steady our minds and remember what we already have. We have learned the First and Second Declensions well enough to recognize them by their Genitive singular endings. When a noun has a Genitive singular ending in -ae, or in -es when the Nominative ends in -e, we know it belongs to the First Declension. When a noun has a Genitive singular ending in -i, we know it belongs to the Second Declension. If we keep those signs clear, the new forms we meet now will not crowd and confuse what we have already mastered.

As before, we must distinguish carefully between what the Nominative ending suggests and what the Genitive ending proves. The Third Declension has many possible Nominative endings. A Third Declension noun may end in vowels such as -a, -e, or -o, and it may also end in consonants such as -c, -d, -l, -n, -r, -s, -t, or -x. Because there are so many Nominative endings, Third Declension nouns can feel more difficult at first than the nouns we have studied before. Yet we should not be discouraged by this variety, because it also signals something helpful: most Latin nouns belong to the Third Declension. Once we learn this declension well, we gain the ability to recognize and understand the forms of hundreds of nouns that appear constantly in Latin.

But we must not decide that a noun belongs to the Third Declension simply because its Nominative ends in one of those letters. The Nominative can mislead us. The only reliable sign remains the Genitive singular ending. All Third Declension nouns have the Genitive singular ending in -is. That is what makes them Third Declension nouns. When we see that ending, we know where we are.

We have already met many Third Declension nouns in our reading of the Gospel of John. Words such as omnis, lux, homo, nomen, lumen, potestas, sanguis, voluntas, caro, pater, veritas, plenitudo, lex, sacerdos, and vox occur frequently, and they belong to the Third Declension precisely because their Genitive singular ends in -is. This is why the Third Declension cannot be treated as a rare or advanced topic. It is the center of the language, and our reading will continually bring us back to it.

Here the importance of stems becomes clearer than ever. A stem is the part of a noun to which the case endings are attached. We do not find the stem by looking at the Nominative form, because the Nominative is often irregular in appearance. We find the stem by looking to the Genitive singular. If we remove the Genitive singular termination, what remains is the stem. This method works across declensions. From musae we remove -ae and find the stem mus-. From libri we remove -i and find libr-. From domini we remove -i and find domin-. From templi we remove -i and find templ-. Now, in the Third Declension, from sermonis we remove -is and find sermon-. From vomeris we remove -is and find vomer-. From sedis we remove -is and find sed-. From temporis we remove -is and find tempor-. From civis we remove -is and find civ-. The endings of declension are added to the stem, not to the Nominative form. Therefore, if we want to decline a noun accurately, we must know its Genitive singular, because that tells us both the declension and the stem.

A Latin dictionary gives us exactly what we need. It will give us the Nominative singular, the Genitive singular, the gender, and the definition. Thus we might see dominus, domini with its gender and meaning, and we might see sermo, sermonis with its gender and meaning. With this information, we are able to decline the noun. We can identify the declension from the Genitive ending, and we can form the stem by removing that ending.

As we proceed, we also remember what we have learned about substantives and adjectives. An adjective noun may be used with a substantive that is expressed or understood, and when an adjective is used with a substantive, it must agree with it in gender, number, and case. If we say sermo elegans, meaning “an elegant speech,” then sermo is the substantive and elegans is the adjective noun, and they must move together through the cases. Thus we say sermonis elegantis for “of an elegant speech,” and a sermone elegante for “from an elegant speech.” Likewise, if we say lapis gravis, meaning “a heavy stone,” we say lapidis gravis for “of a heavy stone,” and in the plural we say lapides graves for “heavy stones,” and lapidibus gravibus for “to heavy stones.” In these examples we see agreement, and we see that the endings follow the noun and adjective each according to its own declension, yet they still match in case, number, and gender.

This agreement becomes more challenging when the substantive is in the Third Declension and the adjective is from another declension, because the outward forms will not look alike even though the grammatical agreement is real. For example, sermo is a Third Declension substantive, but verus is a Second Declension adjective. When we say sermo verus, we mean “a true speech.” When we say sermonis veri, we mean “of a true speech.” When we say sermonem verum, we mean “a true speech” as a direct object. When we say sermonibus veris, we mean “to true speeches.” The endings look different, but the agreement is exact. We do not need to resolve every difficulty of this now. As we learn the declensions fully, and later study adjectives in their own time, this will become clear through repeated experience.

Now we set before ourselves the Third Declension forms in several representative nouns. We begin with a masculine noun of the Third Declension: hic Sermo, meaning “a speech.” In the singular we say hic Sermo in the Nominative, Sermonis in the Genitive meaning “of a speech,” Sermoni in the Dative meaning “to a speech,” Sermonem in the Accusative, O Sermo in the Vocative, and a Sermone in the Ablative meaning “from a speech.” In the plural we say Sermones in the Nominative, Sermonum in the Genitive meaning “of speeches,” Sermonibus in the Dative meaning “to speeches,” Sermones again in the Accusative, O Sermones in the Vocative, and a Sermonibus in the Ablative meaning “from speeches.” Here we see the characteristic Third Declension endings, especially the Accusative singular in -em and the Ablative singular in -e, and in the plural the Dative and Ablative in -ibus.

We then take a feminine noun of the Third Declension: haec Sedes, meaning “a seat.” In the singular we say haec Sedes in the Nominative, Sedis in the Genitive meaning “of a seat,” Sedi in the Dative meaning “to a seat,” Sedem in the Accusative, O Sedes in the Vocative, and a Sede in the Ablative meaning “from a seat.” In the plural we say Sedes in the Nominative, Sedium in the Genitive meaning “of seats,” Sedibus in the Dative meaning “to seats,” Sedes in the Accusative, O Sedes in the Vocative, and a Sedibus in the Ablative meaning “from seats.” Here we see a Genitive plural in -ium, which is one of the important variations within the Third Declension that must be learned by experience.

Next we take a neuter noun of the Third Declension: hoc Tempus, meaning “time.” In the singular we say hoc Tempus in the Nominative, Temporis in the Genitive meaning “of time,” Tempori in the Dative meaning “to time,” Tempus in the Accusative, O Tempus in the Vocative, and a Tempore in the Ablative meaning “from time.” In the plural we say Tempora in the Nominative, Temporum in the Genitive meaning “of times,” Temporibus in the Dative meaning “to times,” Tempora in the Accusative, O Tempora in the Vocative, and a Temporibus in the Ablative meaning “from times.” Here the neuter rule stands out clearly: in each number the Accusative and Vocative are the same as the Nominative. In the plural, the neuter Nominative, Accusative, and Vocative end in -a, as we have already seen in other declensions.

We also study a noun that is common of two genders, meaning it may be masculine or feminine depending on the person referred to: hic et haec Civis, meaning “citizen.” In the singular we say hic et haec Civis in the Nominative, Civis in the Genitive meaning “of a citizen,” Civi in the Dative meaning “to a citizen,” Civem in the Accusative, O Civis in the Vocative, and a Cive in the Ablative meaning “from a citizen.” In the plural we say Cives in the Nominative, Civium in the Genitive meaning “of citizens,” Civibus in the Dative meaning “to citizens,” Cives in the Accusative, O Cives in the Vocative, and a Civibus in the Ablative meaning “from citizens.” Again we see the Genitive plural in -ium, and we also see how a single noun can serve for either gender without changing its declension.

As we compare these nouns, we begin to see a general pattern that will guide our memory, even though the Third Declension will always require experience. In the singular, the Genitive ends in -is and the Dative commonly ends in -i. The Accusative singular for masculine and feminine nouns commonly ends in -em, and the Ablative singular commonly ends in -e. In the plural, the Nominative and Accusative of masculine and feminine nouns commonly end in -es, and the Dative and Ablative commonly end in -ibus. Neuter nouns, as always, have Nominative, Accusative, and Vocative alike, and in the plural these end in -a.

Yet we also notice immediately that the Genitive plural is not always the same. Sometimes it ends in -um, and sometimes it ends in -ium, as we have seen in Sermonum but Sedium, and again in Civium. This is one of the reasons the Third Declension must be mastered by use and repeated reading rather than by trying to force it into an over-systematized set of rules. We will learn these forms as we meet them, and our experience in reading will establish them in the mind far more securely than an attempt to build an artificial system.

If we keep the essential sign fixed—that the Third Declension is known by the Genitive singular ending -is—and if we keep the essential method fixed—that the stem is found from the Genitive singular by removing its termination—then the Third Declension will steadily become familiar. The variety of Nominative endings will no longer intimidate us, because the Genitive will guide us. The apparent complexity will resolve into regular patterns confirmed by repeated use.

Memory Work

1. How many different terminations are found in the Nominative case of the Third Declension?
Eleven: -a, -e, -o | -c, -d, -l | -n, -r, -s, -t, -x.

2. Decline the Third Declension masculine noun hic Sermo. (State the case name, the Latin form and the English.)
Singulariter: Nominativo, hic Sermo, a speech; Genitivo, Sermonis, of a Speech; Dativo, Sermoni, to a Speech; Accusativo, Sermonem, a Speech; Vocativo, O Sermo, O Speech; Ablativo, a Sermone, from a Speech. Pluraliter: Nominativo, Sermones, Speeches; Genitivo, Sermonum, of Speeches; Dativo, Sermonibus, to Speeches; Accusativo, Sermones, Speeches; Vocativo, O Sermones, O Speeches; Ablativo, a Sermonibus, from Speeches.

In short: Sermo, Sermonis, Sermoni | Sermonem, O Sermo, a Sermone | Sermones, Sermonum, Sermonibus | Sermones, O Sermones, a Sermonibus.

3. Decline the Third Declension feminine noun haec Sedes (Seat). (State the case name, the Latin form and the English.)
Singulariter: Nominativo, haec Sedes, a Seat; Genitivo, Sedis, of a Seat; Dativo, Sedi, to a Seat; Accusativo, Sedem, a Seat; Vocativo, O Sedes, O Seat; Ablativo, a Sede, from a Seat. Pluraliter: Nominativo, Sedes, Seats; Genitivo, Sedium, of Seats; Dativo, Sedibus, to Seats; Accusativo, Sedes, Seats; Vocativo, O Sedes, O Seats; Ablativo, a Sedibus, from Seats.

In short: Sedes, Sedis, Sedi | Sedem, O Sedes, a Sede | Sedes, Sedium, Sedibus | Sedes, O Sedes, a Sedibus.

4. Decline the Third Declension neuter noun hoc Tempus (Time). (State the case name, the Latin form and the English.)
Singulariter: Nominativo, hoc Tempus, Time; Genitivo, Temporis, of Time; Dativo, Tempori, to Time; Accusativo, Tempus, Time; Vocativo, O Tempus, O Time; Ablativo, a Tempore, from Time. Pluraliter: Nominativo, Tempora, Times; Genitivo, Temporum, of Times; Dativo, Temporibus, to Times; Accusativo, Tempora, Times; Vocativo, O Tempora, O Times; Ablativo, a Temporibus, from Times.

In short: Tempus, Temporis, Tempori | Tempus, O Tempus, a Tempore | Tempora, Temporum, Temporibus | Tempora, O Tempora, a Temporibus.

5. What special rule applies to Neuter nouns of the Third Declension?
Neuter nouns of the Third Declension have the Accusative and Vocative the same as the Nominative in each Number.

6. Decline the Third Declension common-of-two noun hic et haec Civis (Citizen). (State the case name, the Latin form and the English.)
Singulariter: Nominativo, hic et haec Civis, Citizen; Genitivo, Civis, of a Citizen; Dativo, Civi, to a Citizen; Accusativo, Civem, a Citizen; Vocativo, O Civis, O Citizen; Ablativo, a Cive, from a Citizen. Pluraliter: Nominativo, Cives, Citizens; Genitivo, Civium, of Citizens; Dativo, Civibus, to Citizens; Accusativo, Cives, Citizens; Vocativo, O Cives, O Citizens; Ablativo, a Civibus, from Citizens.

In short: Civis, Civis, Civi | Civem, O Civis, a Cive | Cives, Civium, Civibus | Cives, O Cives, a Civibus.

7. Summary of the Third Declension:

Note to Parent/Praeceptor: See that the Genitive plural termination is sometimes -um and sometimes -ium, depending on the word. Modern efforts to multiply rules and systematize the Third Declension should be ignored. Experience is the only means to mastery.

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