This is the 9163rd most frequent Russian word.
сергей
"Сергей" is a Russian male given name, equivalent to "Sergey" or "Serge" in English.
Here, 'Сергей' is used as a proper noun referring to a person's name.
Меня зовут Сергей.
My name is Sergei.
In this sentence, 'Сергей' is the subject indicating the person performing the action.
Сергей пришёл домой поздно.
Sergei came home late.
Here, 'Сергей' is used as the object in the clause, representing the individual being observed.