The Semantic Web is the web of data. Berners-Lee et al. (2001) defines it as “an extension of the current web in which information is given well-defined meaning, better enabling computers and people to work in cooperation.”
Reference
Berners-Lee, Tim, James Hendler, and Ora Lassila. 2001. “The Semantic Web.” Scientific American, May 2001. https://doi.org/10.1038/scientificamerican0501-34.