This is the 868th most frequent Arabic word.
الثقافي
"Cultural."
Here, "الثقافي" (ath-thaqafi) is used as an adjective to describe "المركز" (almarsa), indicating the center's thematic connection to culture.
المركز الثقافي هو مكان لتبادل الأفكار والمعرفة.
The cultural center is a place for exchanging ideas and knowledge.
Here, "الثقافي" (ath-thaqafi) qualifies "التراث" (at-turaath), describing the heritage as pertaining to culture.
التراث الثقافي يعكس تاريخ الشعوب وحضاراتها.
Cultural heritage reflects the history and civilizations of nations.
In this sentence, "الثقافي" (ath-thaqafi) is modifying "النشاط" (an-nashaat), specifying that the activity is related to culture.