Check in with the Psychonomic Society’s featured digital content all week for a discussion of what working memory is. Starting from a forthcoming paper in Psychonomic Bulletin & Review by Nelson Cowan that describes the 9 (!) definitions of working memory prevalent in published literature, we are considering how it is that working memory can be described in so many distinct ways, whether this is a problem, and if so, how to deal with it. Full-text of Cowan’s paper is freely available, and there will be new reactions each day this week from Steve Lewandowsky, Klaus Oberauer, me, Judith Schweppe, and finally a reply from Nelson Cowan.