This is the 3548th most frequent Turkish word.
sahiplerini
"Owners" or "their owners."
Here, 'sahiplerini' means 'their owners' and identifies the possessors of the books in question.
Kitaplarını sahiplerini bulmak için müzayedeye koydular.
They put their books in an auction to find their owners.
In this sentence, 'sahiplerini' refers to the 'owners' of the dog.
Sokakta gördüğüm köpek sahiplerini çok özlemiş gibi görünüyordu.
The dog I saw on the street seemed to miss its owners a lot.
The term 'sahiplerini' designates the 'owners' of the mentioned valuable items.