Third Declension Nouns
Table of contents
Third Declension
The third declension exhibits the most variety by far 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 where knowing the dictionary entry of a noun comes most in handy; without it, it will be impossible to know the nominative singular form of a third declension noun.
Masculine/Feminine
| Singular | Plural | |
|---|---|---|
| Nominative | -ς, – | -ες |
| Genitive | -ος | -ων |
Neuter
| Singular | Plural | |
|---|---|---|
| Nominative | – | -α |
| Genitive | -ος | -ων |
Third Declension
| Masculine/Feminine | Neuter | |
|---|---|---|
| Nom. sg. | -ς, – | – |
| 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** |
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, in the Week 4 Vocabulary. The noun stem is παιδ-, but the δ of the stem and the σ of the dative plural ending conflict (the formation παιδσιν 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, from the Week 3 Vocabulary. The noun stem is γυναικ-, and the combination of stem plus dative plural ending would result in the form γυναικσιν. The κσ 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.
- 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.
- 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)).