This part of ISO 18451 defines terms that are used in the field of pigments, dyestuffs and extenders. For some terms, reference is made to ISO 4618 in which also terms and definitions for colourants are given, relating to their use in coating materials. In addition to terms in English and French (two of the three official ISO languages), this part of ISO 18451 gives the equivalent terms in German; these are published under the responsibility of the member body for Germany (DIN). However, only the terms and definitions given in the oficial languages can be considered as ISO terms and definitions. NOTE Those terms that are defined elsewhere in this part of ISO 18451 are shown in italics.