The NOMAD Metainfo can be understood as the schema of the NOMAD Archive. The NOMAD Archive data is structured to be independent of the electronic-structure theory code or molecular-simulation, (or beyond). The NOMAD Metainfo can be browsed as part of the NOMAD Repository and Archive web application.
Typically, (meta-)data definitions are generated only for a predesigned and specific scientific field, application, or code. In contrast, the NOMAD Metainfo considers all pertinent information in the input and output files of the supported electronic-structure theory, quantum-chemistry, and molecular-dynamics (force-field) codes. This ensures complete coverage of all material and molecule properties, even though some properties might not be as important as others, or are missing in some input/output files of electronic-structure programs.
The NOMAD Metainfo started within the NOMAD Laboratory. It was discussed at the CECAM workshop Towards a Common Format for Computational Materials Science Data and is open to external contributions and extensions. More information can be found in Towards a Common Format for Computational Materials Science Data (Psi-K 2016 Highlight).