This is the 12183rd most frequent Turkish word.
günlerinin
"Of their days" or "of his/her days" (depending on context).
Here, 'günlerinin' represents possessive form meaning 'her days', depicting a person's past days or moments.
Eski günlerinin hatırası hala aklında.
The memories of her old days are still in her mind.
In this sentence, 'günlerinin' signifies 'her days' with a possessive and plural meaning about the duration of a vacation.
Tatilde tüm günlerinin dolu olduğunu söyledi.
She said that all her days during the vacation were full.
In this example, 'günlerinin' is used to express possession over 'friend's days', reflecting the state or occurrences in their daily lives.