Reference Plant Ontologies are being developed in the context of the Planteome project and are being integrated with the Crop Ontology, which provides harmonized breeders’ trait names, measurement methods, scales and standard variables for many crops. The Oat Trait Ontology is one of these reference plant ontologies integrated within the Crop Ontology. The Oat Trait Dictionary was commissioned by Oat Global (http://oatglobal.org/) to hold the traits used in the T3/Oat database (http://triticeaetoolbox.org/oat/).