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The 2005 Working Drafts of the SKOS Core Vocabulary Specification (aka "SKOS 2005") have been superseded by 2009 versions ("SKOS 2009").

SKOS Simple Knowledge Organization System Reference (2009)


The Simple Knowledge Organization System (SKOS) is a common data model for sharing and linking knowledge organization systems via the Semantic Web.

Many knowledge organization systems, such as thesauri, taxonomies, classification schemes and subject heading systems, share a similar structure, and are used in similar applications. SKOS captures much of this similarity and makes it explicit, to enable data and technology sharing across diverse applications.

The SKOS data model provides a standard, low-cost migration path for porting existing knowledge organization systems to the Semantic Web. SKOS also provides a light weight, intuitive language for developing and sharing new knowledge organization systems. It may be used on its own, or in combination with formal knowledge representation languages such as the Web Ontology language (OWL).

Latest version:

SKOS Extensions Vocabulary Specification (2004)

This document has been superseded.


This document is a reference guide to the SKOS Extensions RDF Vocabulary. SKOS Extensions are a set of terms extending the SKOS Core vocabulary to support some common features of knowledge organisation systems, especially thesauri.

Superseded version: