Noun gender: three genders, decided by the ending
Every Russian noun is masculine, feminine or neuter, and the nominative singular ending tells you which — with a short list of exceptions.
Russian has three grammatical genders and no articles, so gender is carried entirely by the noun's own ending. A noun ending in a hard consonant, in -й or in -ь is masculine: дом, край, день. A noun ending in -а or -я is feminine: ма́ма, кни́га, семья́. A noun ending in -о, -е or -ё is neuter: окно́, мо́ре, ружьё. The gender is a property of the word, not of the thing — there is no logic to learn beyond the ending.
The exceptions are few and you should simply memorise them. Masculine despite the ending: па́па, дя́дя, мужчи́на, ю́ноша — words for men, where natural gender beats the -а. Masculine in -е: ко́фе, which is masculine by long tradition (it once ended in a consonant). Neuter indeclinables: метро́, такси́, кака́о, меню́. And the soft sign splits two ways: но́чь, мышь, дочь, вещь, тетра́дь, пло́щадь are feminine (the so-called third declension), while день, учи́тель, кора́бль and путь are masculine. There is no rule here. Learn the gender together with the word, exactly as you learn its stress.
In a compound the gender follows the head word — the element that carries the meaning and takes the endings. Моско́вский вокза́л is masculine because вокза́л is; Са́довая у́лица is feminine because у́лица is. The adjective simply agrees with whatever the head turns out to be.
Why this matters so early: gender drives two other systems. Adjectives agree with it — большо́й дом, больша́я ко́мната, большо́е окно́, больши́е до́ма. And the past tense of a verb agrees with it — он чита́л, она́ чита́ла, оно́ чита́ло, они́ чита́ли. A wrong guess about gender therefore produces two errors, not one. It is the cheapest accuracy you can buy in Russian.
Examples
- До́м большо́й, маши́на больша́я, окно́ большо́е. The house is big, the car is big, the window is big. — the adjective follows the noun's gender Listen in Russian: Slow in Russian: До́м большо́й, маши́на больша́я, окно́ большо́е.
- Мой па́па — хоро́ший челове́к. My dad is a good man. — па́па ends in -а but is masculine Listen in Russian: Slow in Russian: Мой па́па — хоро́ший челове́к.
- Э́тот ко́фе о́чень кре́пкий. This coffee is very strong. — ко́фе is masculine, so э́тот and кре́пкий are too Listen in Russian: Slow in Russian: Э́тот ко́фе о́чень кре́пкий.
- Моя́ мышь живёт в ко́мнате. My mouse lives in the room. — мышь is feminine despite the soft sign Listen in Russian: Slow in Russian: Моя́ мышь живёт в ко́мнате.
- Сего́дня у нас тяжёлый день. Today we have a hard day. — день is masculine despite the soft sign Listen in Russian: Slow in Russian: Сего́дня у нас тяжёлый день.
- Моско́вский вокза́л о́чень краси́вый. The Moscow station is a very fine building. — a compound takes the gender of its head word Listen in Russian: Slow in Russian: Моско́вский вокза́л о́чень краси́вый.