The Discovery Information Model is a representation of the meaning and structure of data held in the electronic health records that have been published to the Discovery data service. It consists of an ontology of ontologies, a common basic data model, a vocabulary of terms used in the ontology and data model, a set of maps between terms and codes, and a library of various sets for use in query or by the data models. It is designed to help systems and informaticians make sense of the chaos of data from different systems. The model contents are accessed either by APIs or via an open source application : Information Model Manager. In order for machines to understand the content and structure, and to enable interoperability both within healthcare and with other sectors, it uses a set of international standard languages that form the languages of the semantic web. It is not a single information model in the conventional sense. Nor is it a single data model. Whilst there is a single data model that encompasses the data, the expectation is that there is a need for as many data models as there are business requirements. However, because the model uses a common vocabulary semantically defined using ontological techniques, computers that understand the vocabulary can interoperate even when using different data models. This is the basis for the semantic web. Unlike human language, machine based languages must use logical constructs and once the means of using logic is understood then the computers can use the logic to process the data. The model does not own its ontology. Instead it absorbs the best ontologies and supplements with additional content not yet defined. In using the London extension of Snomed-CT, it can generate new concepts and expressions that can be shared across the NHS. Only those concepts that are necessary are created in order to prevent loss of detail.