It is a contested question in contemporary theories of religion whether the concept of religion can be defined in a sound way or not. Many theorists maintain that a universal but delimiting definition is impossible. In this study, by contrast, it is argued that a conceptual analysis of religion that holds universally is perfectly possible because the following thesis can be seen as a necessary and sufficient conceptual condition of what religion is: (R) X is a religion if and only if X is a collection of artifacts which has the proper function of representing a supraphysical world. On this thesis, it is argued that artifacts such as pictorial and verbal representations, rituals, symbols, and various tools constitute religion as a cultural object, which, as a collection of artifacts, has the proper function of representing a conceived world that is not entirely physical, and which, allegedly, is a prerequisite for existential welfare in relation to observance. It is here important to understand what is constitutive for these kinds of conceived worlds. Supraphysical world is defined as follows. Given that the actual world is a physical world, a conception S is a construction of a supraphysical world if and only if both of the following conditions apply to S: (1) Metaphysical component: S is a duplicate of the actual world with the addition of an anti-physical substance. (2) Existential-normative component: S is an alleged prerequisite for existential welfare in relation to observance. The core argument of the study is that (R) holds a priori for the concept of religion and as an a posteriori necessity for every instance of a religion. Apart from discussing the methodological problems of defining religion, the study introduces a new theory of religion in terms of (R). It addresses also issues in the theory of artifacts; in the theory of representations; and in the theory of conceptual analysis.