The term design fiction was originally coined in 2005 by the Science Fiction author Bruce Sterling. In the 10 years since, design fiction has received considerable interest from a range disciplines most notably HCI which increasingly draws upon generative methods and creative practices. In this paper we consider examples of recent HCI research that refers to design fiction in order to highlight commonalities and ambiguities in how the term is interpreted and used. We argue that design fiction is a compelling and powerful concept but is inherently ambiguous. We therefore suggest strategies to disambiguate communications ‘about design fiction’ in order to strengthen applications ‘of design fiction’.