This is the 1802nd most frequent Arabic word.
الديني
Religious.
Here, 'الديني' modifies 'الجانب' describing it as 'religious'.
يناقش الكتاب الجانب الديني للمجتمع.
The book discusses the religious aspect of society.
Here, 'الديني' is used adjectivally to describe 'subjects' with a religious characteristic.
المعلم يدرس موادًا ذات طابع ديني.
The teacher teaches subjects with a religious nature.
In this sentence, 'الديني' qualifies 'debate' to specify that the debate pertains to religion.