This standards purpose is to establish the characteristics and the conformance rules required to synthetically describe the organisation and content of a terminological system in health. This standard has been developed to allow the production of specific standards on categorial structures for particular healthcare subject fields with the minimum requirements to support meaningful exchange of information.This European Standard is applicable to:- facilitate the construction of new terminological systems in a regular form which will increase their coherence and expressiveness;- facilitate maintenance of terminological systems;- increase consistency and cohere