Semantic web is an extension of the World Wide Web that provides a common framework for expressing data in a way that machines can understand and process, thereby enabling data to be shared and reused across applications, enterprises, and community boundaries. As a research field and methodological approach, it investigates methods for structuring web data with formal semantics, typically employing technologies such as RDF, OWL, and SPARQL, to facilitate automated data integration, reasoning, and the development of intelligent data-driven applications and knowledge graphs.