The OpenCyc Knowledge Base
The OpenCyc Knowledge Base consists of code, written in the declarative language CycL, that represents or supports the representation of facts and rules pertaining to consensus reality. OpenCyc is licensed using the Apache License, Version 2, whose text can be found here. The OpenCyc CycL code base is the "Work" referred to in the Apache license. The terms of this license equally apply to renamings and other logically equivalent reformulations of the Knowledge Base (or portions thereof) in any natural or formal language.
The OpenCyc Java API and Other Non-CycL Open Source Code
Some other programs from those listed above are provided as open source. All of the programs of this type that currently ship with OpenCyc use the Apache License, but it is possible that future released programs may use a different license. All license and copyright information for these programs are included in their distributions.
The OpenCyc Knowledge Server
The OpenCyc Knowledge Server consists of a binary derivative version of the Cyc® Inference Engine and Knowledge Base Index, a binary derivative version of the Cyc® Knowledge Base Browser, and a suite of tools for rapidly extracting knowledge from a domain expert.
Cycorp is providing a free-of-charge license to the OpenCyc Knowledge Server that grants the Licensee the irrevocable right to download, to use, and to distribute the OpenCyc Knowledge Server in binary form for commercial or non-commercial use. By obtaining information, software, and/or documentation of the OpenCyc Knowledge Server in whole or in part (collectively, "Material"), you agree to be legally bound by the following terms.
The OpenCyc OWL Ontologies
These files contain an OWL representation of information contained in the OpenCyc Knowledge Base. The content of these OWL files are licensed under the Creative Commons Attribution 3.0 license whose text can be found at http://creativecommons.org/licenses/by/3.0/legalcode. The content of these OWL files, including the OpenCyc content they represent, constitutes the "Work" referred to in the Creative Commons license. The terms of this license equally apply to, without limitation, renamings and other logically equivalent reformulations of the content of these OWL files (or portions thereof) in any natural or formal language, as well as to derivations of this content or inclusion of it in other ontologies.