Each noun in the Russian language has a gender – masculine, feminine or neuter. Grammatical genders have nothing to do with sex. The word стол ( a table) is of masculine gender, the word лампа (a lamp) is of feminine gender, but a table and a lamp have no masculine or feminine features at all.
Scientists suppose that in ancient times, people believed that any thing was alive and had an anima, sort of soul or conciseness, and that anima could be either feminine or masculine. Things that had no anima were neutral. Of course, today nobody would tell you that a table has something that makes it masculine or a lamp has specific feminine features. A grammatical gender is nothing more than what remains ancient beliefs.
How to determine what gender a noun is? The only way is to check a dictionary. A noun has no obvious indications of its gender. For example, мама (mom) is feminine, while папа (dad) is masculine. Both words look alike and have the same endings in all cases. Another example: моль (moth) is feminine, but рояль (piano) is masculine. So just check your dictionary and try to memorize the gender by writing and talking as much as possible.
The good news is that usually, Russian masculine nouns end with a consonant (компьютер, телефон, дом, банк). Russian feminine nouns often end with a vowel -а (клавиатура, машина, квартира, купюра). Many neuter nouns end with -о or -е (поле, море, окно, мыло). This is not a rule, but just a trend that is true for the majority of nouns, but not for all.
Why care about the gender? Because the gender of a noun determines the ending of the following adjective, and the ending of verbs in the past tense. Also you should know the gender of the noun in order to choose the right pronoun – you should always use он (he) for masculine nouns and она (she) for feminine, despite the fact that it is actually “it”. Here are some examples:
M.: Большой, красивый дом. Он мой. (This is a large, beautiful house. It is mine)
F.: Большая, красивая машина. Она моя. (This is a large, beautiful car. It is mine)
N.: Большое, красивое окно. Оно моё. (This is a large beautiful window. It is mine)
Sometimes, Russians argue about a gender furiously. There are some words in Russian that came from other languages and gained a gender by “it looks like”. One of such words is the word кофе (coffee). It looks like a neuter noun (ends with -e), but its gender is masculine, and only poorly educated people say “черное кофе” (black coffee) instead of “черный кофе”.
Which part of Russian grammar do you find the most difficult to learn and understand?