This is the 5295th most frequent Turkish word.
kartını
"Your card" or "the card of yours."
In this context, 'kartını' refers to a card possessed by the subject, functioning as a direct object in the sentence.
Kartını gösterdi ve içeri girdi.
He showed his card and entered.
Here, 'kartını' conveys possession and functions as the direct object of the verb related to forgetting.
Kartını unuttuğu için kütüphaneye giremedi.
He couldn't enter the library because he forgot his card.
In this sentence, 'kartını' indicates possession and serves as the entity being transferred or given.