This is the 1192nd most frequent Russian word.
другу
The Russian word "другу" means "to a friend" (dative case).
The word 'другу' is a dative form used to denote the indirect object, meaning 'to my friend'.
Я дал книгу своему другу.
I gave the book to my friend.
The word 'другу' is in the dative case, showing the beneficiary of the action 'to help'.
Мы всегда идем помогать другу.
We always go to help a friend.
Here 'другу' is the dative case indicating to whom the action of calling was directed.