normdatum

Normdatum is a term used in library and information science to denote standardized, authoritative data about a person, corporate body, work, or subject that is used to normalize references across catalogs and databases. A normdatum entry provides a unique identifier and a controlled form of the name or term, together with variant forms, affiliations, life dates, roles, and related terms. The primary purpose is to disambiguate entities with similar names, ensure consistent spelling, and enable reliable linking and retrieval across systems and languages.

Normdatum entries are typically stored in authority files or authority data systems and are shared as machine-readable records. They may be represented in traditional catalog formats such as MARC authority records or in modern linked-data formats using URIs and RDF. A well-known national authority file is the German Gemeinsame Normdatei (GND), which aggregates names, subjects, and classifications to serve libraries, archives, and other institutions. Other major authority data sets include the Library of Congress Name Authority File (LCNAF) and the VIAF (Virtual International Authority File). The normdatum assigned to an entity serves as a stable identifier that enables interlibrary linking, data merging, and federated search across catalogs and external data sources.

In practice, normdatum support cataloging workflows, metadata harvesting, and digital provenance. By providing a single, authoritative form of an entity’s name and related data, libraries and information systems can improve search accuracy, interoperability, and user discovery.