An UpperOntology is an ontology (or part of an ontology) dealing with very abstract or "meta" concepts. Examples of the sorts of concepts you might find in an UpperOntology would be "discrete entity", "collection of entities", "material entity", "event", "process", etc.
A list of OpenContent upper ontologies can be found on the page UpperOntologies.
Bayle Shanks liked this powerpoint presentation created by Alan Rector for a class. It gives a brief tour through a particular upper ontology, and gives tips on how to build one.
CategoryAboutOntologies?
Define external redirect: CategoryAboutOntologies