This is the 10456th most frequent Polish word.
czwartkowe
"Related to Thursday."
Here, "czwartkowe" qualifies the noun "wydanie" (edition), indicating that it pertains to Thursday.
Kupiliśmy czwartkowe wydanie gazety.
We bought the Thursday edition of the newspaper.
The word "czwartkowe" functions as an adjective, modifying the noun "spotkanie" (meeting), thus describing its occurrence on Thursday.
Czwartkowe spotkanie było bardzo interesujące.
The Thursday meeting was very interesting.
In this sentence, "czwartkowe" is used more abstractly to characterize the noun "rzeczy" (things), suggesting they relate to Thursday.