Russian noun declension.

What declension means

In English, a noun barely changes: "book," "book's," "books." In Russian, a single noun has a different ending for each of the 6 cases, in both singular and plural. That full set of forms is its declension.

The good news: nouns are not memorized one by one. They fall into three regular patterns, and which pattern a noun follows is decided by its gender and its nominative ending. Once you know the pattern, you can produce every case form on demand.

The three declension types

Russian noun declension splits into three groups:

• 1st declension - feminine and some masculine nouns ending in -а / -я: книга (book), неделя (week), папа (dad).
• 2nd declension - masculine nouns ending in a consonant and neuter nouns in -о / -е: стол (table), окно (window), музей (museum).
• 3rd declension - feminine nouns ending in a soft sign -ь: ночь (night), дверь (door), любовь (love).

Gender resolves the one overlap: a noun ending in -ь is 2nd declension if it is masculine (словарь) but 3rd if it is feminine (ночь). Everything else you can read straight off the ending.

Declension tables

Here is the full singular declension for a sample noun of each type. The highlighted part is the case ending.

What to notice: the 1st declension (книга) and 2nd declension (стол, окно) carry most nouns. The 3rd declension (ночь) is the smallest group and keeps -и through most cases. Soft-stem nouns (неделя, музей, море) follow the same patterns with the soft-vowel versions of these endings (-я, -ю, -е stay soft).

Plural endings

The plural is more uniform across types. The nominative plural is where you start, and the rest follow a shared set of endings.

The dative, instrumental, and prepositional plural endings (-ам, -ами, -ах) are the same for every noun, which makes the plural easier than the singular. The genitive plural is the tricky one: it can be a zero ending (книг, окон) or -ов/-ей, depending on the noun.

Common pitfalls

• Mixing up the -ь nouns. A soft sign does not tell you the gender on its own. словарь is masculine (2nd declension), ночь is feminine (3rd). You must learn the gender, then the pattern follows.
• The genitive plural. This is the single hardest ending in Russian declension. Feminine -а nouns often drop to a zero ending (книга → книг), while masculine nouns usually take -ов (столов). It is worth drilling on its own.
• Forgetting that adjectives decline too. Declension is not just for nouns. Adjectives and pronouns take their own case endings and must agree with the noun: новая книга → новой книги → новую книгу.
• Stress shifts. Some nouns move their stress when they decline (окно → окна with stress on the ending). The spelling is regular; the stress sometimes is not, and you pick it up with exposure.