This is the 1471st most frequent Polish word.
dziennik
"Journal," "diary," or "logbook"; also "daily newspaper" depending on context.
Here, 'dziennik' refers to a daily printed publication containing news and articles, e.g., a newspaper.
Codziennie rano czytam dziennik, aby być na bieżąco z wiadomościami.
Every morning I read the daily newspaper to stay updated with the news.
In this context, 'dziennik' is used to mean a type of journal or log used to record details, specifically a reading log here.
Uczeń musi codziennie wypełniać swój dziennik lektur.
The student must fill in their reading journal daily.
Here, 'dziennik' denotes an official log or register, as used in schools to record student attendance and other information.