This used to be a static library but is now available through the
KSL Interactive Ontology Server
The Interactive Ontology Server has many new and updated ontologies; the static versions are now out of date.
This is an electronic library of public ontologies. Ontologies are specifications of conceptualizations, used to help programs and humans share knowledge . In practice they consist of definitions of representational vocabulary, some including axiomatic theories. Most of the files here are in a machine-readable form: KIF  sentences in forms that Ontolingua  can translate into implemented representation languages.
Ontology Library Table of ContentsLook at the Reference Documents section of the index first; these documents introduce and link into the ontologies. This cross indexing service was performed by the latest Ontolingua tools.
It is suggested that you browse the ontologies in their nice, hypertext form first (see above) and then download them in the form you need.
The following files contain the ontology library in various languages:
Note: It is very possible that the .tar.Z files will be older than the latest offerings in hypertext form. Check the file dates carefully. To get the latest individual ontolingua source document, you can view the source file from the hypertext interface and then use your WWW browser to save it as a plain text file.
If you live behind a firewall, (i.e., you can't access internet addresses outside your site) then ftp the file html-ontologies.tar.Z from this directory. It contains the ontology web as a self-contained directory of files that you can browse locally using a WWW browser such as Mosiac.
The ontologies posted here may change and no claims or warrants are made. They may be copyrighted, but the authors give permission to freely distribute the files with the copyright label intact.
See also the WWW-resident