W3C SKOS

A W3C web standard for publishing structured vocabularies, glossaries, and taxonomies in a format that machines can read and link to each other across the web.

The Simple Version

A W3C web standard for publishing structured vocabularies, glossaries, and taxonomies in a format that machines can read and link to each other across the web.

Detailed Explanation

W3C SKOS (Simple Knowledge Organization System) provides an RDF vocabulary for expressing concepts (skos:Concept), their labels (skos:prefLabel, skos:altLabel), definitions (skos:definition), and relationships (skos:broader, skos:narrower, skos:related). It enables knowledge organisation systems to be published as linked data on the Semantic Web, making glossary content machine-readable and interoperable. In AI governance contexts, SKOS is used to publish regulatory vocabularies (EU AI Act terms), domain ontologies, and controlled vocabularies that feed into knowledge graphs and structured metadata. It underpins the W3C Linked Data ecosystem.

Key Characteristics

• W3C standard for expressing vocabularies, taxonomies, and thesauri in RDF
• Key SKOS properties: prefLabel, definition, broader, narrower, related
• Enables machine-readable, interoperable knowledge organisation
• Foundation for Semantic Web and Linked Data vocabulary publishing

Why It Matters

Organisations publishing AI governance glossaries or regulatory term repositories can use SKOS to make their vocabulary machine-readable — enabling integration with knowledge graphs, AI retrieval systems, and regulatory data exchange.

Real-World Analogy

Like a standardised format for library catalogue cards that allows different libraries' catalogues to be combined and searched together — SKOS allows different knowledge organisation systems to be published and linked in a common machine-readable format.

Common Misconceptions

• SKOS is a full ontology language like OWL — SKOS provides light-weight concept organisation; OWL is needed for formal logical axioms and class hierarchies.
• SKOS is obsolete as a standard — it remains the primary W3C recommendation for knowledge organisation systems and is actively used across government, academia, and industry.

Related Terms

• w3c prov o
• knowledge graph
• structured data
• metadata

Sources & Further Reading

• W3C SKOS Reference

W3C SKOS: Direct Definition

A W3C web standard for publishing structured vocabularies, glossaries, and taxonomies in a format that machines can read and link to each other across the web.

Technical Definition

W3C SKOS (Simple Knowledge Organization System) provides an RDF vocabulary for expressing concepts (skos:Concept), their labels (skos:prefLabel, skos:altLabel), definitions (skos:definition), and relationships (skos:broader, skos:narrower, skos:related). It enables knowledge organisation systems to be published as linked data on the Semantic Web, making glossary content machine-readable and interoperable. In AI governance contexts, SKOS is used to publish regulatory vocabularies (EU AI Act terms), domain ontologies, and controlled vocabularies that feed into knowledge graphs and structured metadata. It underpins the W3C Linked Data ecosystem.

Why It Matters

Organisations publishing AI governance glossaries or regulatory term repositories can use SKOS to make their vocabulary machine-readable — enabling integration with knowledge graphs, AI retrieval systems, and regulatory data exchange.