[SKOS](https://www.w3.org/2009/08/skos-reference/skos.html) (Simple Knowledge Organization System) is a W3C standard designed to represent controlled vocabularies, taxonomies, thesauri, and classification schemes in a machine-readable way using [[RDF]]. Think of SKOS as a lightweight ontology vocabulary focused on conceptual labeling and relationships, not formal logic like OWL. Use cases include - Tagging systems (e.g., tagging documents or articles) - Public classification systems (e.g., Library of Congress Subject Headings) - [[controlled vocabulary|Controlled vocabularies]] in open data portals - [[Knowledge graph]] labeling and categorization