This part of ISO 18629 provides a specification of non-primitive concepts of the language, using a set of definitions written in the language of ISO 18629. These definitions provide an axiomatization of the semantics for terminology in this part of ISO 18629. The following is within the scope of this part of ISO 18629: ? definitions of concepts specified in ISO 18629-11, ISO 18629-12 and ISO 18629-14 that are related to resources and resource sets and relations between resources and activities; ? definitions of concepts specified in ISO 18629-11, ISO 18629-12 and ISO 18629-14 that characterize relations between resources and activities.