The word “друг” is a masculine form, and the feminine form is подруга. Note the last word ends in “a”. It usually shows that a noun is feminine.
Он мой друг.
He is my friend.
Она моя подруга.
She is my friend.
These words have different ending depending on the case.
Я знаю его друга. – I know his friend.
Я могу быть твоим другом. – I can be your friend.
Он рассказал мне о своем друге. – He told me about his friend.
Она отправила письмо своему другу. – She sent her friend a letter.
Я иду в кино с подругой. – I’m going to the cinema with my friend (female).
The plural form of the word друг is друзья. For the word подруга is подруги. But when you are talking about a circle of friends wich include both male and female ones you should use the word друзья (for male). Just like in Spanish, for example.
Мы можем быть друзьями. – We can be friends.
У меня много друзей. – I have many friends.
There are some other ways to say “friend” in Russian but they are not so common. The word “дружище” is a slang form of a noun “друг” and means a really good friend. When talking to a friend you can call him that way.
Как дела, дружище? – How are you doing, friend?
Note that this word is more for men. Women don’t normally use this word.
Another slang word for friend is “кореш”. But it’s quite ourdated and was more popular in 90s.
“Товарищ” – a word which was very common in Soviet Russia. People still use it but in more formal situations.
Talking about friends and friendship in Russian
Let’s look at some other examples of using the words related to friends and friendship in Russian (and also some collocations):
friendship – дружба
a true (real) friend – настоящий друг
a close friend – близкий друг
to make friends – подружиться
to be friends (with) – дружить (с)
We are good friends. – Мы хорошие друзья.
He’s my old friend. – Он мой старый друг.
John is his best friend. – Джон его лучший друг.
We have been friends for five years. – Мы дружим пять лет.
If you need a translation of some word or sentence about friends and friendship in Russian just post a comment here. I’ll be glad to help you!