Neuter Nouns in -ος
One neuter class is left, and it is the odd one out in the whole noun system: neuter nouns ending in -ος. το μέρος (“part, place”), το τέλος (“end”), το δάσος (“forest”), το μέγεθος (“size”), το έθνος (“nation”). Two things make them worth their own lesson. FIRST, the ending -ος looks masculine - it is the ending of ο δάσκαλος - so the article is the only thing telling you the gender, which is why this class is the strongest argument in the course for learning every noun WITH its article. SECOND, the declension is unlike anything else you have met: the genitive singular is -ους (μέρους, τέλους), the plural is -η (μέρη, τέλη), the genitive plural is -ών (μερών, τελών) - and the accusative and vocative are IDENTICAL to the nominative in both numbers, so there are really only four distinct forms in the whole table. The stress splits by where the tonos already sits: a PENULT-stressed member keeps it on the stem in the genitive singular and the plural (μέρος → μέρους, μέρη) and moves it only in the genitive plural (μερών), while an ANTEPENULT-stressed member such as μέγεθος moves it forward in the singular genitive and the plural too (μεγέθους, μεγέθη) - the same three-syllable rule that gives άνθρωπος → ανθρώπου.
The rule
Neuter nouns in -ος are the odd class of the whole system, because the ending looks masculine - it is the ending of ο δάσκαλος - and only the article gives the gender away: το μέρος, το τέλος, το δάσος, το μέγεθος, το έθνος. This class is the single strongest argument for storing every noun as article + noun. The declension resembles nothing else you have met: genitive singular -ους (μέρους, τέλους), plural -η (μέρη, τέλη), genitive plural -ών (μερών, τελών) - and since accusative and vocative copy the nominative in both numbers, the entire table holds only four distinct shapes. Stress splits by where the tonos already sits: a penult-stressed member keeps it on the stem (μέρος → μέρους, μέρη) and moves it only in the genitive plural (μερών), while an antepenult-stressed one moves it forward wherever the word grows (μέγεθος → μεγέθους, μεγέθη, μεγεθών).
Paradigm
| Case | Singular | Plural |
|---|---|---|
| Nominative | μέρος | μέρη |
| Accusative | μέρος† | μέρη† |
| Genitive | μέρους | μερών† |
| Vocative | μέρος† | μέρη† |
- In this class the accusative and vocative equal the nominative, in both numbers.
- The genitive plural -ών takes the tonos to the ending (μέρος → μερών).
| Case | Singular | Plural |
|---|---|---|
| Nominative | μέγεθος | μεγέθη† |
| Accusative | μέγεθος† | μεγέθη† |
| Genitive | μεγέθους† | μεγεθών† |
| Vocative | μέγεθος† | μεγέθη† |
- The tonos moves one syllable forward in the plural too (μέγεθος → μεγέθη).
- In this class the accusative and vocative equal the nominative, in both numbers.
- Antepenult-stressed, so the three-syllable rule moves the tonos one forward in the genitive (μέγεθος → μεγέθους) - unlike the penult-stressed μέρος → μέρους.
- The genitive plural -ών takes the tonos all the way to the ending (μέγεθος → μεγεθών).