The facilities provided by Ontolingua are now only available through the

KSL Interactive Ontology Server

The Interactive Ontology Server has many new and updated ontologies as well as many new features relative to Ontolingua 4.0. Anything else you see in this document is old and should be treated only as an historical hint.

Ontolingua is a set of tools, written in Common Lisp, for analyzing and translating ontologies. It uses KIF as the interlingua and is portable over several representation systems. It includes a KIF parser and syntax checker, a cross reference utility, and a set of translators from KIF into implemented representation systems, and a HTML report generator. See below for a more complete description of the services that Ontolingua provides.

This is an overview of ontolingua, with pointers to more information. The sections of this document are:


The documentation for Ontolingua has undergone extensive revision, and is now entirely available on-line in hypertext form (on the World Wide Web).

Documents available:

For an introduction to the ideas underlying ontolingua, see
T. R. Gruber.
A Translation Approach to Portable Ontology Specifications.
Knowledge Acquisition, 5(2):199-220, 1993.
Available at ftp://ksl.stanford.edu/pub/knowledge-sharing/papers/.

Also, if you ever wondered,
What is an ontology? (WWW only)

Also, since Ontolingua is based on the KIF language and the ontological extension to KIF specified in the Frame Ontology, specifications of these should be considered part of the documentation on Ontolingua. KIF is described in the official KIF spec. The Frame Ontology is described in its place in the Ontology web.

Ontolingua Services

Ontolingua is a Common Lisp program. To use Ontolingua, go here

The major services provided by Ontolingua are:

Example Ontologies

There is a directory tree full of example ontologies, now in fully indexed, hypertext format. Ontolingua users are encouraged to share and reuse these ontologies, and contribute theirs.

User Group

There is a mailing list for Ontolingua information and requests: ontolingua@ksl.stanford.edu

To subscribe (or unsubscribe) send mail to ontolingua-request@ksl.stanford.edu

Archives are maintained on the World Wide Web at http://ksl-web.stanford.edu/email-archives/

Tom Gruber <gruber@ksl.stanford.edu>