Third Declension Nouns

The genitive reveals the stem

The third declension is the final major noun family. Unlike the first and second declensions, its nominatives have many different shapes. A dictionary therefore gives you a nominative, a genitive, and an article: σάρξ, σαρκός, ἡ, 'flesh'. Learn all three together.

Remove -ος from the genitive singular to find the stem: σαρκ- from σαρκός. Add endings to that stem, not blindly to σάρξ. The article tells you the gender, which cannot reliably be guessed from the nominative ending.

The familiar case functions have not changed. Nominative is still the subject, genitive still expresses relationships, dative still marks such roles as recipient or means, and accusative still marks a direct object. Only the family of endings is new.

• σάρξ, σαρκός, ἡ — flesh; stem σαρκ-; feminine
• σῶμα, σώματος, τό — body; stem σωματ-; neuter
• ὄνομα, ὀνόματος, τό — name; stem ὀνοματ-; neuter

Endings and consonant collisions

For many masculine and feminine nouns the endings are nominative singular -ς (or a changed stem), genitive -ος, dative -ι, accusative -α; plural -ες, -ων, -σι(ν), -ας. There are exceptions, including some accusatives in -ν. Use the dictionary and a paradigm when the pattern differs.

A stem consonant can merge with σ, just as it did in future verbs. σαρκ- + ς gives σάρξ, and σαρκ- + σι gives σαρξί(ν). Labials give ψ, velars give ξ, and dentals disappear before σ. Thus the stem may be clearer in a genitive than in a nominative or dative plural.

The dative singular is -ι, not the iota subscript seen in λόγῳ or ἀρχῇ. Do not assume a third-declension form ending in -ι is a plural; σαρκί is singular, while σαρξί is plural.

• σαρκί — to/with flesh; dative singular
• σαρκός — of flesh; genitive singular

Neuter nouns in -μα

Many important neuters end in -μα in the nominative but have -ματος in the genitive: σῶμα, σώματος ('body'), ὄνομα, ὀνόματος ('name'), πνεῦμα, πνεύματος ('spirit'). Their stems end in -ματ-, so the τ reappears before most endings.

The neuter rule still holds: nominative, accusative, and vocative match in each number. For σῶμα the singular is σῶμα and the plural is σώματα. Do not confuse σώματα with a first-declension singular just because it ends in α.

The dative plural σωματ- + σι becomes σώμασι(ν), because τ disappears before σ. The other forms make the stem visible: σώματος, σώματι, σωμάτων. Begin with one complete -μα paradigm and use it to recognize the others.

• βλέπω τὰ σώματα. — I see the bodies.
• ἐν τῷ ὀνόματι τοῦ κυρίου — in the name of the Lord

Accent and a practical reading method

Many one-syllable third-declension nouns move their accent to the ending in the genitive and dative: σάρξ, σαρκός, σαρκί, σαρκῶν, σαρξί. This is an accent pattern, not a change of word meaning. Learn the accented genitive with the noun.

When reading an unfamiliar form, start with the article if one is present. Then separate the likely ending, recover the stem, and compare it with a vocabulary entry's genitive. Finally choose a translation that fits the noun's job in the sentence.

Third-declension nouns include more patterns than one lesson can exhaust. This lesson establishes the basic endings and -μα type; irregular and vowel-stem families can be learned on this foundation rather than treated as random exceptions.

Vocabulary (7)

νέος, -α, -ον

new, young

σάρξ, σαρκός, ἡ

flesh

σῶμα, σώματος, τό

body

ὄνομα, ὀνόματος, τό

name

πνεῦμα, πνεύματος, τό

spirit, wind, breath

αἷμα, αἵματος, τό

blood

ῥῆμα, ῥήματος, τό

word, saying