This is the 8496th most frequent Catalan word.
diürna
"Diürna" means "daytime" or "related to the day."
Here, 'diürns' (plural form of 'diürna') describes animals as something characteristic pertaining to daytime activity.
Els animals que són actius durant el dia es consideren diürns.
Animals that are active during the day are considered diurnal.
In this sentence, 'diürn' (masculine form of 'diürna') is used to describe a schedule that occurs during the day.
Aquest horari diürn és perfecte per a mi.
This daytime schedule is perfect for me.
In this sentence, 'diürna' is used as an adjective describing 'light', indicating that the light occurs during the day.