This is the 618th most frequent Finnish word.
vuorokauden
"Vuorokauden" means "of the day (24-hour period)" in English.
Here, 'vuorokauden' refers to the 24-hour day, from one midnight to the next.
Vuorokaudessa on 24 tuntia.
There are 24 hours in a day.
In this sentence, 'vuorokauden' emphasizes the duration of 24 hours during which the subject has been awake.
Olen ollut valveilla vuorokauden.
I have been awake for a whole day.
Here, 'vuorokauden' is used to indicate a specific 24-hour period during which changes can occur.