Universal Decimal Classification

The Universal Decimal Classification (UDC) is the world's foremost multilingual classification scheme for all fields of knowledge; a sophisticated indexing and retrieval tool (read more). UDC is maintained in a database containing more than 70,000 records.

The UDC Summary (udcS) is a selection of 2,600 top-level classes from the UDC, translated into 49 languages. The udcS is continuously updated online with new translations. You can browse udcS content online here.

UDCS Linked Data

Linked Data is structured data that can be interlinked and cross-referenced to make it more useful for both humans and computers. UDC Summary data is published in SKOS (XML/RDF) format. The mapping between UDC and SKOS classes is shown in the table below. UDC linked data is available:

Each record displays the following information (where available):

UDC number (notation)UDC notation is combination of symbols (numerals, signs and letters) that represent a class, its position in the hierarchy and its relation to other classes. Notation is a language-independent indexing term that enables mechanical sorting and filing of subjects. Also called 'UDC number' and 'UDC classmark'skos:notation---
class identifier (URI) A unique identifier assigned to each UDC class. It identifies the relationship between a class' meaning and its notational representationskos:Concept---
broader class (URI)Superordinate class: the class hierarchically above the class in questionskos:broader---
captionVerbal description of the class contentskos:prefLabel---
including noteExtension of the caption containing verbal examples of the class content (usually a selection of important terms that do not appear in the subdivision)skos:noteudc:includingNote
application noteInstructions for number building, further extension and specification of the classskos:noteudc:applicationNote
scope noteNote explaining the extent and the meaning of a UDC class. Used to resolve disambiguation or to distinguish this class from other similar classesskos:scopeNote---
examplesExamples of combination are used to illustrate UDC class building i.e. complex subject statementsskos:example---
see also referenceIndication of conceptual relationship between UDC classes from different hierarchiesskos:related---

The UDC SKOS scheme can be downloaded from http://udcdata.info/udc-scheme.

If you would like more information about UDC Linked Data or the UDC Summary email udcs@udcc.org.