This is the 13473rd most frequent Polish word.
patriotyczne
"Patriotyczne" means "patriotic" in English.
The word "patriotycznego" is used to describe the day as being related to the patriotism displayed during national holidays. It is an adjective modifying the noun "dnia" (day).
Polskie flagi były widziane wszędzie podczas patriotycznego dnia świąt narodowych.
Polish flags were seen everywhere during the patriotic national holiday.
The word "patriotycznej" here modifies the noun "literatury" (literature), and thus describes the literature as possessing a character that inspires or relates to patriotism.
Uczeni dyskutowali na temat wpływu patriotycznej literatury na młodzież.
Scholars discussed the impact of patriotic literature on youth.
In this sentence, "patriotycznej" is again an adjective, describing "tematyce" (theme), expressing that the theme of the songs was related to patriotism.