The CDNO provides structured terminologies to describe nutritional attributes of material entities that contribute to human diet. These terms are intended primarily to be associated with datasets that quantify concentration of chemical nutritional components derived from samples taken from any stage in the production of food raw materials (including from crops, livestock, fisheries) and through processing and supply chains. Additional knowledge associated with these dietary sources may be represented by terms that describe functional, physical and other attributes. Whilst recognising that dietary nutrients within food substrates may be present as complex and dynamic physical and chemical structures or mixtures, CDNO focuses on components typically quantified in an analytical chemistry laboratory. The primary CDNO class ‘dietary nutritional component’ contains hierarchical sets of terms organised to reflect commonly used classifications of chemical food composition. This class does not represent an exhaustive classification of chemical components, but focuses on structuring terms according to widely accepted categories. This class is independent of, but may be used in conjunction with, classes that describe ‘analytical methods’ for quantification, ‘physical properties’ or ‘dietary function’. Quantification data may be used and reported in research literature, to inform food composition tables and labelling, or for supply chain quality assurance and control. More specifically, terms within the ‘nutritional component concentration’ class may be used to represent quantification of components described in the ‘dietary nutritional component’ class. Concentration data are intended to be described in conjunction with post-composed metadata concepts, such as represented by the Food Ontology (FoodOn) ‘Food product by organism’, which derives from some food or anatomical entity and a NCBI organismal classification ontology (NCBITaxon) entity. The common vocabulary and relationships defined within CDNO should facilitate description, communication and exchange of material entity-derived nutritional composition datasets typically generated by analytical laboratories. The organisation of the vocabulary is structured to reflect common categories variously used by those involved in crop, livestock or other organismal production, associated R&D and breeding, as well as the food processing and supply sector, and nutritionists, inlcuding compilers and users of food composition databases. The CDNO therefore supports characterisation of genetic diversity and management of biodiversity collections, as well as sharing of knowledge relating to dietary composition between a wider set of researchers, breeders, farmers, processors and other stakeholders. Further development of the functional class should also assist in understanding how interactions between organismal genetic and environmental variation contribute to human diet and health in the farm to fork continuum.