The managerial, policy, technical and ethical decisions centred on emerging technologies are often hampered by a lack of consensus on what falls within the remit of such decisions. A lack of clarity and agreement on definitions is especially the case for nanotechnology. Given the potential of nanotechnology to underpin the next Schumpeterian economic cycle, this limitation on decision making needs to be taken seriously. Here we add to the literature by providing a pathway for decision makers to understand the nature and value of differing definitions in the important case of nanomaterials. We identified 65 relevant sources, of which 27 provided a definition of the term ‘nanomaterial’. Based on the analysis of the content of these 27 definitions, we generated an analytical taxonomy of definitions of ‘nanomaterials’ from which we constructed seven logical categories. Our analysis provides decision makers with a taxonomy to more precisely understand the diversity of definitions, thereby assisting them in their decision-making processes.