This is the 992nd most frequent Russian word.
олег
"Oleg" is a Russian male given name.
The word 'Олег' is used here as a proper noun, referring to the name of a male individual acting as the subject of the sentence.
Олег пошёл в магазин за продуктами.
Oleg went to the store to get some groceries.
In this sentence, 'Олег' is used as a proper noun and is in the genitive case, 'Олега,' indicating the direct object of the inviting action.
Мы пригласили Олега на вечеринку.
We invited Oleg to the party.
The word 'Олег' is shown in the dative case 'Олегу,' marking the recipient of the subjective impression or opinion.