This is the 123rd most frequent Arabic word.
الفلسطينية
"The Palestinian."
Here, 'الفلسطينية' is an adjective describing 'الفتاة' (the girl), indicating her nationality or cultural background.
الفتاة الفلسطينية تساعد والدتها في المنزل.
The Palestinian girl helps her mother at home.
In this sentence, 'الفلسطينية' is an adjective describing 'المشكلة' (the issue), referring to the issue related to Palestine.
المشكلة الفلسطينية تحتاج إلى حل عادل.
The Palestinian issue needs a fair solution.
The word 'الفلسطينية' functions as an adjective modifying 'الثقافة' (the culture), specifying that it pertains to Palestine.