This is the 584th most frequent Turkish word.
telefonu
"Telefonu" means "the phone" or "his/her/its phone" in English, depending on context.
The word 'telefonu' is in the accusative case here, showing that it is the direct object of the verb 'bıraktım' (I left).
Telefonu masanın üzerinde bıraktım.
I left the phone on the table.
Here, 'telefonu' indicates the phone being the subject in a possessive structure followed by an action 'çaldığında' (when it rang).
Telefonu çaldığında hemen açtım.
I answered the phone as soon as it rang.
In this case, 'telefonu' refers to 'his/her phone,' showcasing ownership through possessive construction.