This is the 4449th most frequent Turkish word.
annesini
"Annesini" means "his/her mother" in Turkish, used as the object of a sentence.
In this sentence, "annesini" is in the accusative case, denoting that the mother ('anne') is the direct object of the verb "seviyor" (loves).
O çocuk, annesini çok seviyor.
That child loves his/her mother very much.
Here, "annesini" again denotes the direct object of the verb "çağıracağım" (will call), showing possession (his/her mother) and the accusative case.
Burada bekle, ben annesini çağıracağım.
Wait here, I will call his/her mother.
In this example, "annesini" refers to the object of "ziyaret" (visit), which requires the accusative case to show the object of visiting and indicates possession.