This is the 8997th most frequent Turkish word.
tatilinizi
"Your vacation/holiday."
In this sentence, 'tatilinizi' refers to the vacation belonging to the person being addressed ('your vacation').
Tatilinizi nerede geçirmek istiyorsunuz?
Where do you want to spend your vacation?
Here, 'tatilinizi' indicates the vacation of the person whose planning considerations are being discussed ('your vacation').
Tatilinizi planlarken dikkat etmeniz gerekenler.
What you need to consider when planning your vacation.
In this example, 'tatilinizi' specifies the vacation that might be extended, belonging to the person being asked ('your vacation').