Relationships in the Dewey Decimal Classification System

The Dewey Decimal Classification (DDC) system is a general knowledge organization tool used worldwide. The system features well-defined categories, well-developed hierarchies, meaningful notation, and a rich network of relationships. The nature of relationships in the DDC is richer than is apparent from a linear view of the system. The DDC accommodates the three basic thesaural relationships in the notational and structural hierarchy; through notes in the schedules, tables, and Manual; and in entries in the Relative Index. Derived relationships are shown through the synthesized notation, or through abridgment leading to broader classification. Options and translations provide alternative relationships. Additional relationships may be displayed through mapping of other thesauri.