This is the 12441st most frequent Swedish word.
skoldag
School day.
Here, 'skoldag' refers to the full day spent at school.
Idag är det en lång skoldag.
Today is a long school day.
In this sentence, 'skoldagen' is used in the definite form referring specifically to the school day happening at that moment or typically experienced.
Min favoritdel av skoldagen är lunchrasten.
My favorite part of the school day is the lunch break.
Here, 'skoldag' again refers to the day spent at school, emphasizing it being shorter than usual.