CBSE currently lacks a universally accepted terminology. Existing component models adopt different component de?nitions and composition operators. We believe that for future research it would be crucial to clarify and unify the CBSE terminology, and that the starting point for this endeavour should be a study of current component models. In this paper, we take this first step and present and discuss a taxonomy of these models. The purpose of this taxonomy is to identify the similarities and differences between them with respect to commonly accepted criteria, with a view to clarification and/or potential unification.