This is the 11203rd most frequent Turkish word.
dördü
"The four of them" or "its/his/her four" depending on context.
Here, 'dördü' refers to four people as a collective unit.
Dördü birlikte sinemaya gitti.
The four of them went to the cinema together.
In this sentence, 'dördü' refers to the time (four o'clock).
Saat dördü geçti, geç kalıyoruz.
It has passed four o'clock; we are getting late.
Here, 'dördü' denotes the quantity of books (four) collectively.