The article explores the notion of «secular» and other terms that include this Latin root – secularization, secularism, de-secularization, and post-secular. All these terms are used in various ways by different researchers and in normatively biased ways both within and beyond academia, yielding much confusion. The author attempts to unpack the meanings behind these terms and organize a certain logical matrix for their use. He then goes back exploring the initial meaning of the term «secular» as coined in early Latin Patristic thus tying it up with a specific western Christian tradition, and he then shows what problems may arise while applying this family of terms to other cultural and religious contexts. The author draws on a vast range of current scholarship and a variety of cross-cultural examples.