Ontologies
- The Generalized Upper Model 2.0
- EuroWordNet
- MIKROKOSMOS (not freely available any more)
- OntoBroker (Inference Engine)
- Protégé (Ontology Editor)
- UMLS MetaThesaurus
- CyC Knowledge Server (Knowledge Base / Inference Engine)
- WordNet - a Lexical Database for English
- Suggested Upper Merged Ontology (SUMO)
- MindNet
- ICD: International Code of Diseases
- UMLS Semantic Network
- CycSecure
- OntoMat (Ontology-based Annotation Tool)
- Medical Subject Headings
- Sigma Knowledge Engineering Environment
- SNOMED: Systematized Nomenclature of Medicine
- SENSUS
- OntoEdit (Ontology Editor)
- OWL Ontology Library
- GermaNet
From a theoretical point of view, ontology is the metaphysical study of the nature of being and existence. In practice, an ontology is normally viewed as a formal representation of all semantic objects and their connections in a Universe of Discourse. Mapping these semantic objects onto language units (words, phrases, text segments, etc.) is the task of semantic processing in NLP.
Ontology