As history teachers, we talk about concepts all the time. We know that pupils need to understand them in order to make sense of the past. Precisely what we mean when we talk about concepts is less clear, however. Research into how history teachers talk about their practice suggests that, for example, the distinction they draw between concepts and skills is still, at times, a blurred one. This may, of course, be a matter of semantics: we may use the terminology differently but still have a solid understanding of the kinds of concepts and skills that shape our teaching and our discipline. A lack of clarity could, however, become problematic when we are invited to engage in cross-curricular discussions with our colleagues. The training materials for the Foundation Subjects Strand of the Key Stage 3 Strategy (a strategy of the British government to raise standards in schools in England) for example, include a module entitled ‘Big concepts and skills’. The kinds of concepts discussed in that module bear little resemblance to the those we would recognise as historians. The emphasis is on metacognition (i.e. thinking about how we think and learn) rather than on the kinds of second-order or substantive concepts with which we are familiar or the ways we use second-order concepts to create and reveal rigour in an enquiry question across a history lesson sequence. This is not surprising really - the Foundation Subjects Strand has to be suitably generic to take account of a variety of subjects and is clearly not the place to tackle the particular concepts of an individual subject. This may not be too big a problem as long as we are clear about the kinds of ‘big concepts’ that are important to us as historians. Jannet van Drie and Carla van Boxtel are particularly interested in substantive concepts (e.g. church, democracy, revolution, and empire) rather than the second-order concepts (e.g. cause, consequence, significance, change) that shape types of historical question. Here, they report on a research project into concept mapping as a way of promoting deeper understanding of these difficult and complex terms. They provide a timely reminder that such concepts lie at the heart of historical understanding. In doing so, they also remind us of the importance of being careful about our very usage of the term. It has suddenly become fashionable to use ‘concept’ to describe all kinds of things. All the more important, then, that we are very clear about the meaning it holds for us.