The rapidity of technological change has produced a myriad of disciplines in the past two decades: interaction design, interface design, user interface (UI) design, user experience (UX) design, experience design, interactive design. While these disciplines are distinct, there are also overlaps. However, there is one element that crosses the boundaries of all these disciplines – interactivity. The proliferation of digital media is happening so rapidly that those working in related design disciplines have little time to consider the new paradigms that have emerged. At the very least, it is important to critically examine these design disciplines, if only to clarify the distinctions between these disciplines. The paper seeks first to establish these distinctions, and secondly to highlight the ways in which interactivity connects them together. It is hoped that doing this will create a foundation upon which a common vocabulary can be developed: one that is shared and understood by all those who work in these disciplines.