This is the 579th most frequent Serbian word.
стојановић
"Стојановић" is a Serbian surname, derived from the given name "Стојан" (Stojan).
Here, 'Стојановић' functions as a name representing a family unit.
Породица Стојановић живи у тој кући.
The Stojanović family lives in that house.
In this sentence, 'Стojановићем' is a proper noun used in instrumental case as a part of a formal reference to a person.
Сусрео сам се са господином Стojановићем јутрос.
I met Mr. Stojanović this morning.
The word 'Стojановић' is used here as a noun referring to a specific surname.