This is the 87th most frequent Polish word.
niedzielę
The Polish word "niedzielę" means "Sunday" (accusative or locative case).
Here, 'niedzielę' is a specific temporal reference meaning 'Sunday', in the accusative case as it's used with the preposition 'w' in connection to time.
W niedzielę będziemy mieć spotkanie rodzinne.
On Sunday, we will have a family gathering.
In this sentence, 'niedzielę' is used as a direct object meaning 'Sunday', in the singular accusative case, indicating the time being referred to.
Często spędzam niedzielę na relaksie.
I often spend Sundays relaxing.
Here, 'niedzielę' serves as a direct object in the accusative case, denoting the day of the week that is the subject of the described activity.