This part of ISO/IEC 15026 defines terms and establishes an extensive and organized set of concepts and their relationships, thereby establishing a basis for shared understanding of the concepts and principles central to ISO/IEC 15026 across its user communities. It provides information to users of the subsequent parts of ISO/IEC 15026, including the use of each part and the combined use of multiple parts.Coverage of assurance for a service being operated and managed on an ongoing basis is not covered in ISO/IEC 15026.