Nouns of the third declension

Two declensions have carried you this far. The third is the varied one, and it works differently: instead of one pattern you learn a habit.

The numbers are worth having. Classify every common noun in the New Testament by the genitive its lexicon gives it, and third declension nouns are 587 of the 1,835 — about a third of the different words, and a little under a third of the running text. The second declension is the opposite: 558 words carrying 41% of it. So a second declension noun is one you meet again and again, and a third declension noun is more often one you meet once. That is exactly what makes the habit worth more than the paradigms.

The endings that are always there

The stems vary enormously. The endings barely vary at all, and three of them will carry you.

Genitive singular in -ος, dative singular in -ι, dative plural in -σι(ν). Those three are nearly invariable, and none of them belongs to the first or second declension. Seeing one is enough to tell you where you are.

Find the stem in the genitive

Here is the habit, and it is the whole chapter.

The nominative hides the stem. The genitive shows it. A lexicon gives you both for exactly this reason — σάρξ, σαρκός — and the second of the pair is the one to learn.

Take -ος off the genitive and you have the stem. σαρκός gives σαρκ-, and every other form is built on that: σαρκί (39 occurrences), σάρκα (37), σάρκας (7). The nominative σάρξ is the odd one out, because κ and ς collided and became ξ.

So when a third declension word will not yield, do not stare at the form in front of you. Ask what its genitive would be.

Consonant stems: σῶμα and σάρξ

The largest group. The stem ends in a consonant, and the nominative is where it gets damaged.

σῶμα, σώματος — stem σωματ-, "body". Greek will not end a word in τ, so the nominative simply drops it. The same happens to every -μα noun, and there are a great many: πνεῦμα, πνεύματος (379 occurrences), ὄνομα, ὀνόματος, ῥῆμα, ῥήματος. All neuter.

Καὶ ὁ λόγος σὰρξ ἐγένετο καὶ ἐσκήνωσεν ἐν ἡμῖν

"And the Word became flesh and dwelt among us." Later in the same verse: παρὰ πατρός, πλήρης χάριτος καὶ ἀληθείας — πατρός and χάριτος are both third declension genitives, and both show you their stems.

Vowel stems: πίστις and πόλις

A smaller group but a common one, and it breaks the rule above. These nouns have a genitive in -εως, not -ος.

πίστις, πίστεως, "faith" (242 occurrences) · πόλις, πόλεως, "city" (162) · δύναμις, δυνάμεως, "power" (119).

The nominative singular ends -ις and the genitive -εως. Learn the pair and the group is done; the plural nominative and accusative are both -εις, which is the one place they overlap.

The related -ευς nouns work the same way: βασιλεύς, βασιλέως, "king", and ἀρχιερεύς, ἀρχιερέως, "chief priest", both frequent in the Gospels.

The family words

Three of the commonest nouns in the New Testament are third declension, and all three change their stem between one case and the next.

πατήρ, πατρός, "father" (413) · ἀνήρ, ἀνδρός, "man, husband" (216) · γυνή, γυναικός, "woman, wife" (212).

γυνή is the one to look at twice. Nothing in the nominative prepares you for γυναικός, and the vocative is γύναι — which is how Jesus addresses his mother at Cana (John 2:4) and Mary at the tomb (John 20:15).

These are not learned by rule. They are learned by meeting them, which is what the deck is for.

The dative plural, where the stem gets crushed

The dative plural adds -σι(ν) straight onto the stem, and whatever consonant is already there has to survive the collision. Usually it does not.

χειρ- gives χερσίν, with the ι squeezed out of the middle. ἀνδρ- gives ἀνδράσιν and πατρ- gives πατράσιν, both inserting an α to make the join pronounceable. The commonest of all is ἔθνεσιν, 31 occurrences, from ἔθνος.

These are the forms most likely to stop you, because the stem you were relying on is no longer visible. The -σι(ν) is the clue — but only half of one, because a verb's third person plural ends the same way. ἔθνεσιν is a noun in the dative plural; ποιοῦσιν is "they do". Establish which kind of word you have first, and then -σι(ν) settles the case.

The article carries you

Now the reassurance, and it is a real one.

You almost never have to work a third declension form out cold, because Greek nouns usually come with the article — and the article you learned in chapter 4 has not changed. τῆς σαρκός is genitive singular feminine whether or not you can parse σαρκός; τοῖς ἔθνεσιν is dative plural on the strength of τοῖς alone, and neuter once you know ἔθνος.

So the third declension is much less work than its thirty-odd paradigms suggest. Read the article, learn the genitive with every new noun, and let the rest come from meeting the words.