This is the 153rd most frequent Russian word.
сутки
A 24-hour period; day and night.
This usage of 'сутки' refers to a full day, encompassing a 24-hour period.
Сутки прошли быстро.
The day passed quickly.
Here, 'сутки' designates a 24-hour shift or work period.
Мы работаем сутки через трое.
We work one day on and three days off.
In this context, 'сутки' indicates a time span of 24 hours required for a task or event.