The Third Declension

The first and second declensions were tidy: once you saw χώρα or λόγος, you knew every form. The third declension is where Greek stops holding your hand. It is huge, and it includes many of the most common nouns in the language, and its nominative singular often hides the stem. The good news is that one set of endings covers almost all of it. The work is in finding the stem.

Pronunciation key as before: capital syllable = accent, ē = eta, ō = omega, ü = upsilon, ē also = ει, oo = ου, h = rough breathing. A macron on ā or ī marks a long vowel where it matters; υ is always ü.

The endings

Here is the basic set for masculine and feminine nouns, with neuters beside them. A dash means the stem appears with no ending, or with sound changes you will see in the examples.

Two old rules from the second declension still hold. Neuter nominative, accusative and vocative are always the same as each other, and neuter plurals in those cases end in -α. The genitive plural is -ων in every declension.

Why the genitive must be memorized

Look at these nominatives: φύλαξ, σῶμα, ῥήτωρ, ἐλπίς. You cannot see the stem in any of them. The nominative singular often adds -ς, which collides with the last consonant, or drops consonants that Greek cannot end a word with. The genitive singular, though, is just stem + -ος, so the stem shows plainly.

That is why dictionaries list a third declension noun with three pieces of information: the nominative, the genitive ending, and the article. For example φύλαξ, -ακος, ὁ means "nominative φύλαξ, genitive φύλακος, masculine." Learn every new noun this way, out loud: "φύλαξ, φύλακος, ὁ." It feels slow for a week and then saves you hundreds of hours.

Consonant stems

φύλαξ, φύλακος, ὁ: guard (stem φυλακ-)

The accent of a noun is persistent (Lesson 3): it tries to stay where the nominative has it. In the genitive plural the long ω forces it one syllable to the right, φυλάκων. Labial stems behave the same way: ἡ φλέψ, φλεβός, "vein," dative plural φλεψί(ν). The stem consonant meets σ and you get ψ or ξ.

σῶμα, σώματος, τό: body (stem σωματ-)

Neuters in -μα, -ματος are a big, reliable group, and many reached English: πρᾶγμα "deed, matter," ὄνομα "name," στόμα "mouth," χρῆμα "thing" (plural χρήματα, "money"), δρᾶμα "action, play." In the dative plural the τ drops before σ: σωματ-σι becomes σώμασι(ν) (Smyth 250).

ῥήτωρ, ῥήτορος, ὁ: speaker, orator (stem ῥητορ-)

Liquid stems (ending in λ or ρ) are the friendliest: the ρ simply stays before -σι. The vocative ῥῆτορ uses the short stem vowel, and the accent turns circumflex because the second syllable is now short. Nasal stems (ending in ν) lose the ν in the dative plural: ὁ δαίμων, δαίμονος, "divine power," dative plural δαίμοσι(ν); ὁ ἀγών, ἀγῶνος, "contest," dative plural ἀγῶσι(ν).

The dative plural in one table

The -σι(ν) ending is the only one that touches a consonant, so this is where third declension spelling changes cluster.

Sigma stems: γένος, γένους, τό

Some stems end in σ. Greek dislikes a σ between two vowels, so it drops out, and the vowels left behind contract. The stem of γένος, "race, family, kind," is γενεσ-. Smyth 263 to 264 shows the uncontracted forms in parentheses; here they are in the right-hand column so you can see the machinery.

Contractions to know: ε + ο = ου, ε + ι = ει, ε + α = η, ε + ω = ω. The nominative γένος looks like a second declension word, but do not be fooled: its genitive is γένους, never γένου, and it is neuter. Others like it: τὸ ἔτος "year," τὸ τεῖχος "wall," τὸ ξίφος "sword," τὸ ὄρος "mountain," τὸ πλῆθος "crowd, number," τὸ ἔθνος "nation, people."

Many names in -ης are masculine sigma stems: Σωκράτης [sō-KRA-tēs], genitive Σωκράτους, dative Σωκράτει, accusative Σωκράτη (or Σωκράτην), vocative Σώκρατες. You will hear "ὦ Σώκρατες" on nearly every page of Plato.

I-stems: πόλις, πόλεως, ἡ

The stem of πόλις, "city, city-state," ends in ι. In Attic the ι appears only in the nominative, accusative and vocative singular. Everywhere else it shows ε, and the genitive ending is -ως. Smyth 268.

Three oddities. The accusative singular is -ν, not -α. The accusative plural πόλεις borrows the nominative form. And πόλεως and πόλεων keep the accent on the first syllable even though the last vowel is long. That breaks the usual accent rule, and the reason is historical: the genitive singular was once πόληος (the form Homer has), and the long and short vowels later swapped places without the accent moving (Smyth 34). The genitive plural copied it. Just learn it.

Many abstract nouns follow πόλις: ἡ δύναμις "power," ἡ φύσις "nature," ἡ στάσις "faction, civil strife," ἡ ποίησις "making, poetry," ἡ ὕβρις "violent arrogance." English took a lot of them over directly. Homer and Herodotus keep the ι throughout (πόλιος, πόλιι), which is one of the Ionic features you will meet in Lesson 21.

One more family you will see at once: βασιλεύς

Stems in -ευ are common for people's roles. ὁ βασιλεύς [ba-si-LEUS] "king": genitive βασιλέως, dative βασιλεῖ, accusative βασιλέᾱ, vocative βασιλεῦ; plural βασιλῆς (older Attic, later βασιλεῖς), βασιλέων, βασιλεῦσι(ν), βασιλέᾱς (Smyth 275). Like it: ὁ ἱππεύς "horseman," ὁ ἱερεύς "priest." In Xenophon, βασιλεύς with no article usually means the Persian King.

Gender and agreement

The third declension has all three genders, and the ending does not always tell you which. -μα nouns are neuter, -ος/-ους nouns like γένος are neuter, -ις/-εως nouns like πόλις are feminine, -ευς nouns are masculine. Beyond that, trust the article in your vocabulary list.

Adjectives keep their own endings. ὁ ἀγαθὸς φύλαξ, τοῦ ἀγαθοῦ φύλακος, τῷ ἀγαθῷ φύλακι: the adjective is second declension and the noun is third, and they agree perfectly in gender, number and case. The article is your best friend here, since it always shows the case clearly even when the noun does not.