This part of ISO/IEC 11179 specifies rules and guidelines for constructing definitions for data elements. Only semantic structures of data element definitions are addressed; specifications for formatting the definitions are deemed unnecessary for the purposes of this part of ISO/IEC 11179.
Although these definitional rules and guidelines pertain to data elements, they can also be applied in formulating definitions for other types of data constructs such as entity types, entities, relationships, attributes, object types (or classes), objects, segments, composites, code entries, and messages.
The definitional rules and guidelines in this part of ISO/IEC 11179 do not always apply to terminological definitions found in glossaries and language dictionaries. Differences exist between the rules that apply in a language dictionary, and the rules that apply in a data dictionary. For example, terms in a language dictionary may have multiple definitions in the dictionary, whereas data dictionary definitions must be unique within a dictionary and have a single meaning.
Many data element definitions include terms that themselves need to be defined (e.g., charge, allowance, delivery). Some of these terms may have different definitions in different industrial sectors. Therefore, there is a need for most data dictionaries to establish an associated glossary of terms used in the definitions. The area(s) of use for each term is identified in the glossary.