Cyc

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Clockwise: Logos for Cyc's Knowledge Base, Inference Engines, Actionable Output, Intelligent Data Selection
Original author(s)	Douglas Lenat
Developer(s)	Cycorp, Inc.
Initial release	1984; 40 years ago (1984)
Stable release	6.1 / 27 November 2017; 6 years ago (2017-11-27)
Written in	Lisp, CycL, SubL
Type	Ontology and knowledge base and knowledge representation language and inference engine
Website	www.cyc.com

Cyc (pronounced /ˈsaɪk/ SYKE) is a long-term artificial intelligence project that aims to assemble a comprehensive ontology and knowledge base that spans the basic concepts and rules about how the world works. Hoping to capture common sense knowledge, Cyc focuses on implicit knowledge that other AI platforms may take for granted. This is contrasted with facts one might find somewhere on the internet or retrieve via a search engine or Wikipedia. Cyc enables semantic reasoners to perform human-like reasoning and be less "brittle" when confronted with novel situations.

Douglas Lenat began the project in July 1984 at MCC, where he was Principal Scientist 1984–1994, and then, since January 1995, has been under active development by the Cycorp company, where he was the CEO.