This is the 8042nd most frequent Polish word.
niedzieli
"Niedzieli" means "Sunday" in English.
Here, 'niedzieli' is used in the locative case, referring to 'Sunday' as a specific day when the event occurred.
W niedzieli odwiedziłem rodzinę.
On Sunday, I visited my family.
In this case, 'niedzieli' appears in the genitive case, showing anticipation towards the day.
Nie mogę doczekać się niedzieli.
I can't wait for Sunday.
Here, 'niedzieli' is used again in the genitive case, expressing the reason or cause for the store being closed.