OpenCyc is the open source version of the Cyc technology, the world's largest and most complete general knowledge base and commonsense reasoning engine. OpenCyc can be used as the basis of a wide variety of intelligent applications such as:
* rapid development of an ontology in a vertical area
* email prioritizing, routing, summarization, and annotating
* expert systems
* games

The Cyc ontology now contains virtually all of Cyc's hundreds of thousands of terms, along with millions of assertions relating the terms to each other, forming an upper ontology whose domain is all of human consensus reality.

OpenCyc for the Semantic Web provides semantic web endpoints for OpenCyc concepts.

URIs 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:

* -- using the English label for the concept, or
* -- using the concept's permanent identifier.

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

The OpenCyc Collection: "type of person classified by activity" is available at:
* Unique ID: [ Mx4rvWgxLZwpEbGdrcN5Y29ycA ]
* English ID: [ PersonTypeByActivity ]

Used in Dbpedia. The following query when entered into the Dbpedia SPARQL Webform"lists type of person classified by activity". Currently the results are definitive, i.e. not all activity classification are available in Dbpedia.

?s rdf:type <>