GREEK · LESSON 7
σάρξ
Third Declension
The trickiest declension. The stem is hidden in the nominative — you have to find it from the genitive. Once you can do that, the endings are simple.
01 / 22
⚠ The key gotcha
The Stem Is Hidden
For 1st and 2nd declension, the stem stays the same in every form. λόγος, λόγου, λόγῳ — stem λογ- visible everywhere.
Third declension is sneakier. The stem often gets distorted in the nominative singular by collisions with the case ending.
σάρξ — nom sg gives you nothing
The genitive σαρκός reveals the true stem: σαρκ-. The κ is invisible in the nom sg because κ + σ collapsed to ξ.
3rd-decl nouns are listed in dictionaries with two forms: nominative AND genitive. The genitive reveals the stem.
02 / 22
Three steps
Finding the Stem
- Take the genitive singular form. Example: σαρκός.
- Drop the genitive ending -ος. What remains is the stem: σαρκ-.
- Add the case endings below to that stem.
Always memorize 3rd-declension vocabulary as three forms: nominative, genitive, article. σάρξ, σαρκός, ἡ.
03 / 22
Memorize these
The 3rd-Declension Endings
| Masc / Fem | Neuter |
|---|
| sg | pl | sg | pl |
|---|
| Nom | - / -ς | -ες | - | -α |
| Gen | -ος | -ων | -ος | -ων |
| Dat | -ι | -σι(ν) | -ι | -σι(ν) |
| Acc | -α / -ν | -ας | - | -α |
- Gen sg is always -ος — the key to finding any stem.
- Dat pl -σι(ν) often clashes with the stem (consonant changes).
- Neuter rule: nom = acc, both singular and plural.
04 / 22
Pattern 1 — Mute stems (κ, γ, χ)
σάρξ ("flesh") — κ-stem
| Singular | Plural |
|---|
| Nom | σάρξ (σαρκ + ς → ξ) | σάρκες |
| Gen | σαρκός | σαρκῶν |
| Dat | σαρκί | σαρξί (σαρκ + σι → ξι) |
| Acc | σάρκα | σάρκας |
Mute + σ collapses: κ+σ→ξ, π+σ→ψ, τ+σ→σ (the dental drops).
05 / 22
Pattern 2 — Liquid stems (ν, ρ)
αἰών ("age, eternity") — ν-stem
| Singular | Plural |
|---|
| Nom | αἰών (no ending) | αἰῶνες |
| Gen | αἰῶνος | αἰώνων |
| Dat | αἰῶνι | αἰῶσι(ν) (ν drops before σ) |
| Acc | αἰῶνα | αἰῶνας |
Liquids (λ, ρ) and nasals (μ, ν) interact more peacefully with endings, but often shed a letter at the nominative or in the dative plural.
06 / 22
Famous irregular
πατήρ ("father") — Three-Stem Alternation
| Singular | Plural |
|---|
| Nom | πατήρ | πατέρες |
| Gen | πατρός | πατέρων |
| Dat | πατρί | πατράσι(ν) |
| Acc | πατέρα | πατέρας |
Three-form stem alternation: πατήρ (long ē) → πατρ- (no vowel) → πατέρ- (with vowel). Inherited from PIE.
Same pattern in: μήτηρ ("mother"), θυγάτηρ ("daughter"), ἀνήρ ("man"). The vocative πάτερ (Lord's Prayer opening) is pure stem.
07 / 22
⚠ Total stem hiding
γυνή ("woman") — The Worst Offender
Unlike every other 3rd-decl noun where the nominative at least hints at the stem, γυνή gives you nothing — there is no κ visible at all.
| Singular | Plural |
|---|
| Nom | γυνή (irregular) | γυναῖκες |
| Gen | γυναικός | γυναικῶν |
| Dat | γυναικί | γυναιξί(ν) (κ + σι → ξι) |
| Acc | γυναῖκα | γυναῖκας |
221 NT occurrences. The genitive reveals the true stem γυναικ-. This is why "always use the genitive" is non-negotiable.
08 / 22
Pattern 3 — A huge category
πνεῦμα ("spirit") — -ματ Neuter
| Singular | Plural |
|---|
| Nom | πνεῦμα (τ drops) | πνεύματα |
| Gen | πνεύματος | πνευμάτων |
| Dat | πνεύματι | πνεύμασι(ν) |
| Acc | πνεῦμα (neuter rule) | πνεύματα |
Every -μα noun follows this pattern. Once you know πνεῦμα, you know ὄνομα (name), σῶμα (body), αἷμα (blood), θέλημα (will), ῥῆμα (word), σπέρμα (seed) — dozens.
09 / 22
Pattern 4 — Vowel stem
βασιλεύς ("king") — -εύς Pattern
| Singular | Plural |
|---|
| Nom | βασιλεύς | βασιλεῖς |
| Gen | βασιλέως | βασιλέων |
| Dat | βασιλεῖ | βασιλεῦσι(ν) |
| Acc | βασιλέα | βασιλεῖς |
Same pattern: ἀρχιερεύς (high priest), γραμματεύς (scribe), ἱερεύς (priest). Vowel-stem subgroup of 3rd declension.
10 / 22
Pattern 5 — Theologically critical
πίστις ("faith") — -ις/-εως Pattern
| Singular | Plural |
|---|
| Nom | πίστις | πίστεις |
| Gen | πίστεως | πίστεων |
| Dat | πίστει | πίστεσι(ν) |
| Acc | πίστιν | πίστεις |
The diagnostic: gen sg -εως. If you see it in the lexicon, you know this pattern. Same family: πόλις (city), δύναμις (power), ἀνάστασις (resurrection).
💡 Tip — nom pl and acc pl are identical (πίστεις). The article disambiguates: αἱ πίστεις = nom; τὰς πίστεις = acc.
11 / 22
⚠ Looks 2nd-decl but isn't
ἔθνος ("nation") — -ος/-ους Neuter
| Singular | Plural |
|---|
| Nom | ἔθνος | ἔθνη (ε+α → η) |
| Gen | ἔθνους (ε+ο → ου) | ἐθνῶν |
| Dat | ἔθνει | ἔθνεσι(ν) |
| Acc | ἔθνος | ἔθνη |
⚠ Trap: ἔθνους vs λόγου — both look like genitives, but λόγου is 2nd-decl masc (-ου) while ἔθνους is 3rd-decl neut (-ους). The article also helps: both take τοῦ, but the patterns differ.
💡 τὰ ἔθνη ("the nations / the Gentiles") appears 150+ times in the NT.
12 / 22
A pattern that recurs everywhere
The Square of Stops
Greek consonants come in 3 families × 3 manners. Memorize this once — applies to 3rd decl, futures, aorists, perfects.
| Unvoiced | Voiced | Aspirated | + σ becomes... |
|---|
| Labial (lips) | π | β | φ | ψ |
| Velar (back) | κ | γ | χ | ξ |
| Dental (teeth) | τ | δ | θ | σ (dental drops) |
When a stop collides with σ: labial+σ → ψ, velar+σ → ξ, dental+σ → σ. So σαρκ-+σ = σάρξ; ἐλπιδ-+σ = ἐλπίς.
13 / 22
Foundation for many lessons
The Square Recurs Everywhere
The single most reusable consonant rule in Greek. You'll see it again in:
- Future tense (Lesson 18) — formative is σ. πέμπω → πέμψω (labial), διώκω → διώξω (velar), πείθω → πείσω (dental).
- First aorist (Lesson 15) — same pattern with σα formative. ἔπεμψα, ἐδίωξα, ἔπεισα.
- Perfect middle/passive (Lesson 20) — consonant collisions with stem-final stops.
- Aorist passive (Lesson 17) — θη combining with stem-final stops.
Memorize the Square cold now. Save yourself many hours of confusion later.
14 / 22
Vocabulary highlights
σάρξ & πνεῦμα
σάρξ, σαρκός, ἡ — "flesh"
~147x. In Paul, often means not just bodily flesh but the whole orientation of fallen humanity (Rom 8). But John 1:14 — ὁ λόγος σὰρξ ἐγένετο ("the Word became flesh") — uses it in the bodily sense. Context decides.
πνεῦμα, πνεύματος, τό — "spirit, breath, wind"
~379x. Neuter (τό) — so the Holy Spirit is grammatically it in Greek. Covers literal wind/breath, human spirit, and divine Spirit. John 3:8 plays on this — "the wind/spirit blows where it wishes."
15 / 22
More vocabulary highlights
πατήρ, πίστις, χάρις
πατήρ, πατρός, ὁ — "father"
~414x. Three-form stem alternation. Vocative πάτερ (Lord's Prayer opening) is pure stem — no ending.
πίστις, πίστεως, ἡ — "faith, trust, faithfulness"
~243x. διὰ πίστεως ("through faith" — Eph 2:8) uses gen sg. The semantic range — belief, trust, faithfulness — is the site of major theological argument. English: epistemology.
χάρις, χάριτος, ἡ — "grace, favor, gift"
~156x. Stop-stem (τ + σ → σ). The cornerstone Pauline term. τῇ χάριτί ἐστε σεσῳσμένοι ("by grace you are saved") uses dat sg. English: charity, eucharist, charisma.
16 / 22
Sermon on the Mount
Matthew 5:13-14 — Salt and Light
Ὑμεῖς ἐστε τὸ ἅλας τῆς γῆς·
Ὑμεῖς ἐστε τὸ φῶς τοῦ κόσμου.
"You are the salt of the earth. You are the light of the world."
- τὸ ἅλας ("salt") — 3rd-decl neuter, gen sg ἅλατος. Predicate nominative.
- τῆς γῆς — gen sg of ἡ γῆ (1st decl, contracting).
- τὸ φῶς — 3rd-decl neuter ("light"), gen sg φωτός.
- τοῦ κόσμου — 2nd-decl masc ("of the world").
Three short verses, three predicate nominatives — each a vocational claim.
17 / 22
Words from the cross
Luke 23:46 — "Father, into your hands..."
Πάτερ, εἰς χεῖράς σου παρατίθεμαι τὸ πνεῦμά μου.
"Father, into your hands I commit my spirit."
- Πάτερ — vocative singular of πατήρ. Drops the ending — pure stem.
- εἰς χεῖράς σου — "into your hands" (preposition + acc; χείρ is 3rd-decl).
- τὸ πνεῦμά μου — "my spirit" (acc, direct object of παρατίθεμαι "I commit").
Three 3rd-declension nouns in one short verse. One of the seven last words.
18 / 22
Reading practice
Three Declensions in One Sentence
τὸ πνεῦμα τοῦ θεοῦ
to pneuma tou theou
"the Spirit of God" — 3rd-decl neut + 2nd-decl masc gen.
ὁ Χριστὸς ἀκούει τὰς προσευχὰς τῶν ἁγίων
ho Christos akouei tas proseuchas tōn hagiōn
"Christ hears the prayers of the saints" — note ἀκούω + accusative here (sometimes + genitive).
ὁ πατὴρ τῶν φωτῶν
ho patēr tōn phōtōn
"the Father of lights" (James 1:17) — 3rd-decl ρ-stem + 3rd-decl τ-stem gen pl.
ἡ χάρις τοῦ κυρίου ἡμῶν
hē charis tou kyriou hēmōn
"the grace of our Lord" (Pauline benediction). 3rd-decl τ-stem + 2nd-decl gen.
19 / 22
Cultural / theological note
Why Theological Vocabulary Lives Here
Look at the most theologically loaded NT nouns:
πνεῦμα (spirit) · σάρξ (flesh) · πίστις (faith) · χάρις (grace) · ἐλπίς (hope) · ἀνάστασις (resurrection) · βασιλεύς (king) · πόλις (city) · ἔθνος (nation) · ὄνομα (name) · σῶμα (body).
All third-declension. Not coincidence. The 3rd declension preserved the older, more conservative Indo-European stem types. The 1st and 2nd declensions are later reorganizations. The deep, ancient terms — body, spirit, name, hope, faith — kept their archaic stems.
The chapter where Greek looks hardest is the chapter where the most important vocabulary lives. Don't quit here.
20 / 22
In summary
The Essentials
- Find the stem from the genitive, never from the nominative. Drop -ος; what remains is the stem.
- One ending set for masc/fem; slightly different for neuter. Gen sg is always -ος. Neuter rule: nom = acc.
- Six patterns: mute (σάρξ), liquid (αἰών, πατήρ), -ματ neuter (πνεῦμα), -εύς (βασιλεύς), -ις/-εως (πίστις), -ος/-ους neuter (ἔθνος).
- Square of Stops: labial+σ→ψ, velar+σ→ξ, dental+σ→σ. Recurs in futures, aorists, perfects.
- γυνή is the worst offender — nom hides the κ entirely. Genitive γυναικός reveals the stem.
- Most theologically loaded NT nouns are 3rd-declension. The investment pays off.
21 / 22
End of Lesson 7
Every Declension Is Now in Your Toolkit
τὸ πνεῦμα τοῦ θεοῦ
1st declension (feminine), 2nd declension (masculine/neuter), 3rd declension (mixed gender, hidden stems). You can now find the case and gender of any NT noun.
Drill the lexicon entries: nominative + genitive + article. The stem follows the genitive.
Next: Lesson 8 · Personal & Demonstrative Pronouns
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