Third Declension Nouns

Table of contents

1. Nouns Review
2. Third Declension
3. Third Declension Endings
4. Declining a Third Declension Noun
5. Third Declension Nouns in Practice: Using the Definite Article
6. Third Declension Dative Plurals
7. Alternate Pattern Third Declension Nouns
   1. Family Relationships
   2. -ις, -εως
   3. -ος, -ους
   4. βασιλεύς

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Nouns Review

Until this point of the semester, in terms of nouns and adjectives, we have worked exclusively with first- and second-declension endings. As discussed in the Nouns Overview, a declension is defined as a group to which a noun (or adjective) belongs that shares similar ending patterns. The nouns of the first declension, for example, share endings that exhibit a lot of the letters α or η, while nouns of the second declension share endings that exhibit a lot of the letters ο or ω.

As a quick reminder, we determine which declension a noun belongs to based on its genitive singular ending, i.e., the letters at the end of the noun’s second principal part. If the genitive singular ends in the letters -ας or -ης, then the noun belongs to the first declension (e.g., ψύχη, ψύχης, f. - soul). If the genitive singular ends in the letters -ου, then the noun belongs to the second declension (e.g., ἵππος, ἵππου, m./f. - horse), unless its nominative singular ends in -ας or -ης, in which case it belongs to the first declension (e.g., μαθητής, μαθητοῦ, m. - student).

Third Declension

We now add the third declension into the mix, also known as the consonant declension. Again, the declension to which a noun belongs determines what endings we apply to the noun’s stem to decline it into different cases and numbers. The cases (nominative, genitive, dative, and accusative) and the numbers (singular or plural) mean the same things as in first and second declension nouns – all we are adding into the mix now is a new set of endings that can indicate those cases and numbers.

Like the nouns we already know, a third declension noun can be identified by its genitive singular ending: -ος. Sometimes, a third declension noun will have a genitive singular that ends in -εως or -ους; we’ll discuss those below under the discussion of -ος genitives, which make up most of the third declension nouns we’ll engage with this semester.

Again, note that this -ος ending must apply to the genitive singular, not to the first principal part (the nominative singular). Thus:

• κόρος, κόρου, m. - boy is a second declension noun (-ος occurs in the first principal part, and the second principal part ends in -ου), but
• ὄνομα, ὀνόματος, n. - name is a third declension noun (-ος occurs in the second principal part)

Third Declension Endings

The endings for third declension nouns break down into one set for masculine/feminine nouns and another set for neuter nouns (similar to second declension nouns). The endings are as follows:

	Masculine/Feminine	Neuter
Nom. sg.	–	–
Gen. sg.	-ος	-ος
Dat. sg.	-ι	-ι
Acc. sg.	-α	[same as nom.]
Nom. pl.	-ες	-α
Gen. pl.	-ων	-ων
Dat. pl.	-σι(ν)	-σι(ν)
Acc. pl.	-ας	-α

Some general rules to note:

• The third declension exhibits a lot of variety in terms of what can appear in the nominative singular; there is no one catch-all ending, though some third declension nouns exhibit a sigma or a sigma sound (e.g., in the letter ψ or ξ) in the nominative singular. This is why the dictionary entry of a noun, especially a third-declension noun, is essential to know; without it, it will be impossible to know the nominative singular form of a third declension noun.

• In the neuter accusative singular, note that the notation [same as nom.] means that the neuter accusative singular is spelled exactly the same as the neuter nominative singular. This follows the same rule that we’ve been following all semester: a neuter noun, adjective, or pronoun looks exactly the same across the nominative and accusative within the same number (singular or plural). Thus, ὄνομα (from ὄνομα, ὀνόματος, n. - name) can be either neuter nominative or accusative singular, and we need to use context clues to help us figure out which it is in the context of a sentence. For example:

  • ὁ κόρος τὸ τοῦ διδασκάλου ὄνομα ἤκουσεν. In this sentence, τὸ … ὄνομα can be either nominative or accusative and thus either the subject or the direct object of ἤκουσεν. However, we can use both ὁ κόρος, which has to be masculine nominative singular and cannot be anything else, and the meaning of τὸ ὄνομα as “name” to realize it is a direct object: The boy heard the name of the teacher. (It wouldn’t make as much sense to say “The name of the teacher heard”, especially since it leaves “the boy” out of the sentence.)

Declining a Third Declension Noun

Similar to first and second declension nouns, we can populate the first two cells of a declension chart for a third declension noun because the dictionary entry gives us its nominative singular and genitive singular. Thus, for the noun παῖς, παιδός, m./f. - child, our declension chart begins:

	Form
Nom. sg.	παῖς
Gen. sg.	παιδός
Dat. sg.
Acc. sg.
Nom. pl.
Gen. pl.
Dat. pl.
Acc. pl.

To decline a third declension noun further, we first need to form the noun stem by going to the genitive singular form and chopping off the -ος ending. Note that this must happen with the genitive singular; we cannot decline off the nominative singular, since in many cases there will be a spelling conflict.

Thus, the stem for παῖς becomes παιδ-, and based on the endings for third declension masculine/feminine nouns, we form the remainder of the chart as follows:

	Form
Nom. sg.	παῖς
Gen. sg.	παιδός
Dat. sg.	παιδί
Acc. sg.	παιδά
Nom. pl.	παῖδες
Gen. pl.	παίδων
Dat. pl.	παισί(ν)*
Acc. pl.	παῖδας

* The dative plural drops the δ out of the form; we will discuss this in the next section.

Third Declension Nouns in Practice: Using the Definite Article

While learning a new set of endings and holding them in balance with the first and second declension endings can be confusing, keep in mind that you still have the same help from the definite article that you did for first and second declension nouns. The definite article has only one set of forms that does not change, regardless of what declension noun it’s being used with. Thus:

• ὁ κόρος τὸν στρατιῶταν εἶδεν. The boy saw the soldier (first declension).
• ὁ κόρος τὸν ἵππον εἶδεν. The boy saw the horse (second declension).
• ὁ κόρος τὸν ἀνδρὰ εἶδεν. The boy saw the man (third declension: ἀνήρ, ἀνδρός, m. - man, husband).

The only thing that changes between these three sentences is the noun that forms the direct object, one from each of the declensions, and because of the changes in declension, the endings on each noun are different: -αν for στρατιῶταν, -ον for ἵππον, and -α for ἀνδρά. However, note that because each noun is masculine accusative singular, the definite article being paired with each remains the same: τὸν. Even if you were shaky on your noun declensions, the definite article can help you determine how the noun following it is being used in the sentence.

Third Declension Dative Plurals

Note that almost all the endings across the three declensions begin with a vowel. The one exception is the dative plural ending of the third declension: -σι(ν). The sigma that begins the ending often comes into conflict with a noun stem that ends in a consonant, and it often transforms the noun stem in interesting ways.

For example, note the noun παῖς, παιδός, m./f. - child. The noun stem is παιδ-, but the δ of the stem and the σ of the dative plural ending come into conflict (the formation παιδσιν, “paidsin”, would have sounded odd to the Greeks). The sibillance (the hissing quality) of the σ carries more weight than the δ, so in the conflict, σ wins out, the δ disappears, and the dative plural form of παῖς becomes παισίν.

Note another example, though, in γυνή, γυναικός, f. - woman, wife. The noun stem is γυναικ-, and the combination of stem plus dative plural ending would result in the form γυναικσιν, “gunaiksin”. The κσ / “ks” sound, however, actually constitutes a letter in the Greek alphabet: ξ. Thus, the dative plural of γυνή is γυναιξί(ν).

You can look at the complete noun paradigm charts to see other examples of the 3rd declension dative plural ending in action, but here are some general rules:

• If the noun stem ends in a velar plosive (γ, κ, χ), that stem consonant will contract with the -σ- of the dative plural ending to form the letter ξ (thus γυνή > γυναιξίν).
• If the noun stem ends with a labial plosive (β, π, φ), that stem consonant will contract with the -σ- of the dative plural ending to form the letter ψ.
• If the noun stem ends with a rho, it will remain, and the -σι(ν) ending will simply get attached to that stem. For example, μάρτυς, μάρτυρος, has a noun stem of μαρτυρ-; thus, its dative plural form is μάρτυρσι(ν).
• The -σ- of the dative plural ending will sometimes knock out weaker dental consonants like δ, τ, or θ or combinations like ντ (thus ποίημα > ποιήμασιν)
• Sometimes, such a knocking-out will result in a lengthening of the vowel left over at the end of the stem (for example, γέρων, γέροντος, has the stem γεροντ-; the -σ- of the ending knocks out the -ντ-, and the remaining ο (γερο-) lengthens into -ου-, and the final dative plural form becomes γέρουσι(ν)).

These rules are overwhelming to try to understand, let alone memorize, to the point that I will explicitly tell you if you are looking at a dative plural form and its first principal part. More on this in class.

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Alternate Pattern Third Declension Nouns

Some third declension nouns will exhibit declension patterns that do not fall into the ones described above, due to various morphological idiosyncracies that require much more time with Greek to understand. I’ll provide declension charts for each of the third declension nouns that fall into these patterns, but only in order for you to reference them: you will not be held responsible for memorizing these.

Family Relationships

The nouns πατήρ, πατρός (“father”); μήτηρ, μητρός (“mother”); and θυγάτηρ, θυγατρός (“daughter”) look like regular third declension nouns, but while their endings will look roughly like third declension endings, their stems are variable and irregular across their eight forms, often without any rhyme or reason why, e.g., an extra -ε- shows up in some places. The chart for these three nouns follows:

	πατήρ	μήτηρ	θυγάτηρ
Nom. Sg.	πατήρ	μήτηρ	θυγάτηρ
Gen. Sg.	πατρός	μητρός	θυγατρός
Dat. Sg.	πατρί	μητρί	θυγατρί
Acc. Sg.	πατέρα	μητέρα	θυγατέρα
Nom. Pl.	πατέρες	μητέρες	θυγατέρες
Gen. Pl.	πατέρων	μητέρων	θυγατέρων
Dat. Pl.	πατράσι(ν)	μητράσι(ν)	θυγατράσι(ν)
Acc. Pl.	πατέρας	μητέρας	θυγατέρας

-ις, -εως

Third declension nouns that have a nominative singular ending in -ις and a genitive singular ending in -εως can be declined using the following pattern (the bolded endings assume chopping the -εως off the genitive singular form before declining all the way down). Nouns from the Exam 3 Vocabulary that fall into this pattern are δύναμις, πόλις, and φύσις.

	πόλις
Nom. sg.	πόλις
Gen. sg.	πόλεως
Dat. sg.	πόλει
Acc. sg.	πόλιν
Nom. pl.	πόλεις
Gen. pl.	πόλεων
Dat. pl.	πόλεσι(ν)
Acc. pl.	πόλεις

-ος, -ους

Third declension nouns that have a nominative singular ending in -ος and a genitive singular ending in -ους can be declined using the following pattern (the bolded endings assume chopping the -ους off the genitive singular form before declining all the way down). Nouns from the Exam 3 Vocabulary that fall into this pattern are γένος, μέρος, and πλῆθος.

	γένος
Nom. sg.	γένος
Gen. sg.	γένεως
Dat. sg.	γένει
Acc. sg.	γένος
Nom. pl.	γένη
Gen. pl.	γενῶν
Dat. pl.	γένεσι(ν)
Acc. pl.	γένη

βασιλεύς

The noun βασιλεύς, βασιλέως, m. - king exhibits a declension pattern that holds onto a lot of archaic forms:

	βασιλεύς
Nom. sg.	βασιλεύς
Gen. sg.	βασιλέως
Dat. sg.	βασιλεῖ
Acc. sg.	βασιλέα
Nom. pl.	βασιλεῖς
Gen. pl.	βασιλέων
Dat. pl.	βασιλεῦσι(ν)
Acc. pl.	βασιλέας