A free, formal ontology in first order logic with domain ontologies totalling 20,000 concepts and 60,000 axioms, with mappings to all of WordNet.
Suggested Upper Merged OntologyThe Suggested Upper Merged Ontology (SUMO) - Ontology Portal
A free, formal ontology in first order logic with domain ontologies totalling 20,000 concepts and 60,000 axioms, with mappings to all of WordNet.
Suggested Upper Merged Ontology