O-DEF™ Standard The Open Data Element Framework (O-DEF) (see References) is a standard of The Open Group based on ISO/IEC 11179 that defines a framework for describing common data element concepts, with an initial index (to be extended over time) of object classes, properties, and roles. (A data element concept is a generic data element, with an object class and property, but no defined value domain.) The O-DEF Standard aids interoperability by enabling basic units of data to be classified, using specific object class and property codes, so that equivalences and similarities between the data can be easily determined. The O-DEF Standard also incorporates codes from existing international standards that can become plug-ins; for example, the product codes in the O-DEF Standard are drawn from the UNSPSC.