"The scale of the Cyc Project   elicits awe-struck appreciation   from supporters and critics alike." ~ L.A. Times June 21, 2001

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 contains the full set of (non-proprietary) Cyc terms as well as millions of assertions about the. Cycorp offers this ontology at no cost and encourages you to make use of it as you see fit. For more information and to download OpenCyc, please visit OpenCyc.org.

Cycorp also makes a complete version of Cyc, including many more assertions and additional NL capabilities available at no cost for research purposes. Please check out ResearchCyc for licensing and downloading information.