This is the 12767th most frequent Turkish word.
istiridyenin
"Of the oyster" or "belonging to the oyster."
Here 'istiridyenin' is used in the genitive case to refer to the possession of the pearl inside the oyster.
İstiridyenin içindeki inci çok değerlidir.
The pearl inside the oyster is very valuable.
In this sentence, 'istiridyenin' serves in the genitive case to show connection to the oyster's shell.
İstiridyenin kabuğu çok serttir.
The shell of the oyster is very hard.
Here 'istiridyenin' is used in the genitive case, forming a question regarding the oyster.