Generally a completely unambiguous, declarative, formal, highly restricted language

There are a multitude of ontology languages. Each of them seeks to remove ambiguity and perfectly encapsulate clear information and knowledge.

Examples

  • Common Logic
  • Knowledge Interchange Format (KIF)
  • Web Ontology Language (OWL)
  • Resource Description Framework (RDF)
  • OntoUML (an extension of UML)
  • IDEF5 (see: IDEF)
  • Object-Process Methodology (see: OPM)
  • Attempto Controlled English

Source

Ontology language - Wikipedia