“Diversity” is the focus of a wide-ranging corpus of normative discourses, institutional structures, policies and practices in business, public sector agencies, the military, universities and professions. Here, a brief account of the rise and diffusion of the term is provided. It now addresses a wide variety of social differences, while at least six distinct facets or goals of diversity policy can be discerned. Ambiguity, multivocality and banality are key characteristics of diversity discourse, but these function to strengthen, rather than weaken, the spread and acceptance of the notion. In many settings the commitment to diversity is mainstreamed, expected, and even taken-for-granted. Diversity discourse is related to ongoing processes of social diversification, but its diffusion is not driven by these processes. Overall, despite its many imprecisions, the impacts of the diversity corpus entail a transformation, or at least refinement, of the social imaginary.