The aim of this paper is to examine the oft-heard concern that quality or quality-of-life cannot be defined. This concern persists today, even in the presence of countless studies that claim to be assessing quality or quality-of-life. There is obviously a disconnect here that warrants some attention, if not explanation. In this study, I summarize the extent of this disconnect and offer a number of potential explanations of why this situation exists. I review the role that operational definitions, statistical and empirical models, and content-specific definitions play in defining quality and/or quality-of-life. I conclude that none of these approaches provide a comprehensive definition of quality or quality-of-life. In its stead, I will argue that quality or quality-of-life represents a distinctive pattern of thinking. I establish this pattern by examining the cognitive–linguistic basis of these definitions and argue that when this is done it will be possible to identify an universal cognitive (hybrid) construct that describes how a person thinks about all types of qualitative assessments. The implication of this is that for a study to claim that it is defining or assessing quality or quality-of-life, it will first have to demonstrate the presence of the elements of this hybrid construct.