This is the 548th most frequent Slovenian word.
tednu
"To the week" or "in the week" (dative/locative singular of "teden" - week).
Here, 'tednu' is used in the locative case to specify a time frame within which the action occurred.
V tem tednu sem prebral tri knjige.
This week, I read three books.
In this sentence, 'tednu' is in the dative case to indicate the indirect object of the action.
Naslednjemu tednu bomo posvetili več pozornosti.
We will devote more attention to the next week.
Here, 'tednu' is used in the accusative case due to the preposition 'za', indicating the duration of time.