This is the 2080th most frequent Turkish word.
çalıştılar
"They worked."
The word "çalıştılar" here indicates the past tense of 'they worked' in third-person plural form.
Onlar geçen yıl büyük bir projede çalıştılar.
They worked on a big project last year.
In this context, "çalıştılar" describes an action completed in the past, with emphasis on the time frame yesterday night.
Dün gece geç saatlere kadar çalıştılar.
They worked until late at night yesterday.
Here, "çalıştılar" refers to a collective effort by the team in the past, leading to a positive outcome.