This part of ISO 13399 specifies a reference dictionary for reference systems for cutting tools, together with their descriptive properties and domains of values.This part of ISO 13399 specifies a reference dictionary containing:— definitions and identifications of the classes of reference systems for cutting tools, with an associated classification scheme;— definitions and identifications of the data element types that represent the properties of reference systems for cutting tools;— definitions and identifications of domains of values for describing the above-mentioned data element types.Each class, property or domain of values of this application domain constitutes an entry of the reference dictionary defined in this part of ISO 13399. It is associated with a computer-sensible and human-readable definition, and with a computer-sensible identification. Identification of a dictionary entry allows unambiguous reference to it from any application that implements the information model defined in ISO 13399-1.Definitions and identifications of dictionary entries are defined by means of standard data that consist of instances of the EXPRESS entity data types defined in the common dictionary schema, resulting from a joint effort between ISO/TC 184/SC 4 and IEC SC3D, and in its extensions defined in ISO 13584-24 and ISO 13584-25.