Data Catalog Vocabulary — a W3C standard for describing datasets and data services in a catalogue using a common vocabulary.
DCAT provides a standard set of metadata fields for describing datasets: title, description, publisher, keywords, licence, distribution formats, update frequency, and more. When data portals use DCAT, their catalogues become interoperable — search engines and aggregators can harvest metadata automatically without custom integration work.
DCAT is used by the Government of Canada's open data portal, the European Data Portal, and many national and municipal open data platforms. DCAT-AP is a European application profile that extends DCAT with additional requirements.
Example: The federal open data portal at open.canada.ca publishes DCAT metadata for every dataset. A researcher can query the DCAT endpoint to get a machine-readable list of all available datasets, their formats, licences, and update dates — without visiting each dataset page individually.