This Recommendation | International Standard provides: a) a language (the enterprise language) comprising concepts, structures, and rules for developing, representing, and reasoning about a specification of an Open Distributed Processing (ODP) system from the enterprise viewpoint (as defined in Rec. ITU-T X.903 | ISO/IEC 10746-3); b) rules which establish correspondences between the enterprise language and the other viewpoint languages (defined in Rec. ITU-T X.903 | ISO/IEC 10746-3) to ensure the overall consistency of a specification. The language is specified to a level of detail sufficient to enable the determination of the compliance of any modelling language to this Recommendation | International Standard and to establish requirements for new specification techniques. This Recommendation | International Standard is intended for use in preparing enterprise viewpoint specifications of ODP systems, and in developing notations and tools to support such specifications. As specified in clause 5 of Rec. ITU-T X.903 | ISO/IEC 10746 3, an enterprise viewpoint specification defines the purpose, scope and policies of an ODP system. This Recommendation | International Standard is a refinement and extension of Rec. ITU T X.903 | ISO/IEC 10746 3, clauses 5 and 10, but does not replace them. This Recommendation | International Standard refines and extends the definition of how ODP systems are specified from the enterprise viewpoint, and is intended for the development or use of enterprise specifications of ODP systems.