Formalized Common Knowledge



Semantic Web










OpenCyc for the Semantic Web

Now it is even easier to use the rich and diverse collection of real-world concepts in OpenCyc to bring meaning to your semantic web applications! The full OpenCyc content is now available both as downloadable OWL ontologies as well as via semantic web endpoints (i.e., permanent URIs). These URIs return RDF representations of each Cyc concept as well as a human-readable version when accessed via a Web Browser.

Semantic Web Endpoints

The semantic web endpoints for OpenCyc concepts are available in versions containing permanent concept identifiers as well as versions using language-specific labels. For example, the concept "Game" may be accessed via either:

For simplicity, the current (i.e., most recent) version of the concept will always be available at:

While the natural language labels may be more convenient for casual browsing, the label is subject to change and, therefore, the URIs using the permanent identifiers should be used in applications for that require reliable access to these concepts. Web services will be available shortly that, among other things, will support mapping between concepts and their expressions in natural language.

Downloadable OpenCyc OWL files

The full OpenCyc content is available for download in the following OWL files:

Last updated: July 10, 2012