For putting nouns into the plural we have to add the letter -ы. The very important rule you need to know is that we never have the letter –ы after these letters: к, г, ш, щ, ж, ч, х (about how to remember them easily read here)
In case if there is one of these letters in the end of a word, the ending is –и (not ы):
- банк – банки (a bank – banks)
- парк – парки (a park – parks)
- гараж – гаражи (a garage – garages)
The same thing happens if there is the soft mark (ь) or й in the end. But the difference is that we are replacing them (not adding after) with the -и:
- ночь – ночи (a night – nights)
- отель – отели (hotel – hotels)
- музей – музеи (museum – museums)
Regarding the feminine nouns (More about genders here), we are replacing the last vowel with the -ы or -и. We replace -а with the -ы, and we replace -я with the -и.
- машина – машины
(машинаы)(a car – cars) - идея – идеи an idea – ideas
And don’t forget that it is impossible to have the letter -ы after к, г, ш, щ, ж, ч, х. So if the last letter -a follows one of those letters, you should replace it with the -и (not -ы)
- девушка – девушки
(девушкы)(a girl – girls) - собака – собаки (a dog – dogs)
So about masculine and feminine nouns it is clear. We use endings -ы or -и. But neuter gender nouns make plural in a little different way. For neuter nouns we have to replace the last letter -о with the -а, and if a noun ends with the –е, we replace it with the –я.
- окно – окна (a window – windows)
- море – моря (a sea – seas)
We have also some exceptions that make plural in a different way. You just have to remember them.
PLURAL NOUNS. EXCEPTIONS
- Друг – Друзья (friend – friends)
- Брат – Братья (brother – brothers)
- Муж – Мужья (husband – husbands)
- Жена – Жёны (wife – wifes)
- Сестра – Сёстры (sister – sisters)
- Дерево – Деревья (tree – trees)
- Стул – Стулья (chair – chairs)
- Город – Города (city – cities)
- Паспорт – Паспорта (passport – passports)
- Ребёнок – Дети (child – children)
- Человек – Люди (person – people)
- глаз – глаза (eye – eyes)
- дом – дома (house – houses)
- доктор – доктора (a doctor – doctors)
- профессор – профессора (a professor – professors)
- хозяин – хозяева (owner – owners)
- мастер – мастера (a master – masters)