In early 21st century, the question “Is Turkey becoming secularized contrary to popular belief?” was one of the discussions occupying Turkish public opinion. These discussions led to the encounter of two different concepts of secularization, “theological (Islamic)” and "metaphysical", and to put forward different claims using the same concept. Hence, it became evidentwas understood that a discussion was necessary to understand what secularization is and what it is not before starting any debate on Turkey's secularization. That is because the metaphysical discussion that defines secularization as the decline in the social influence of metaphysical realm (religion, religion-like mechanisms, folk religions, superstitious beliefs, etc.) is overshadowed by the Islamic definition describing secularization as "irreligiousness" or "non-Islamism". Therefore, discussingTo understand the social transformation in Turkey, this article attempts to explain that metaphysical rather than theological definition of secularization is necessary for understanding the social implications of the process of modernization.