Semantic Web

Noun · Open Source · Origin: 2001

Definitions

Semantic Web is a vision and set of technologies for extending the World Wide Web so that data is machine-readable and can be shared, linked, and reasoned about across different applications and organizations. Proposed by Tim Berners-Lee (the inventor of the web) in 2001, the Semantic Web layers structured metadata on top of existing web content using standards like RDF (Resource Description Framework), OWL (Web Ontology Language), and SPARQL (a query language for RDF data). Instead of web pages designed only for human reading, the Semantic Web creates a web of data where information has explicit meaning defined by ontologies and vocabularies. Knowledge graphs (like Google's Knowledge Graph and Wikidata) are practical implementations of Semantic Web principles. While the full vision of a globally interconnected web of machine-readable data has not been fully realized, its technologies power search engine rich results, linked open data initiatives, and enterprise data integration. Schema.org provides a widely adopted vocabulary for structured data markup.
In plain English: A vision of the internet where data is organized and labeled so clearly that computers can understand and connect information across websites on their own, not just display it for humans.

2001: Tim Berners-Lee, James Hendler, and Ora Lassila publish 'The Semantic Web' in Scientific American, envisioning machine-readable web data
2006: Linked Data principles are formalized, making the semantic web more practical with RDF and SPARQL
2010s: Schema.org and JSON-LD bring lightweight semantic markup to mainstream websites, though the grand vision remains partly unfulfilled