Ontology language

In computer science and artificial intelligence, ontology languages are formal languages used to construct ontologies. They allow the encoding of knowledge about specific domains and often include reasoning rules that support the processing of that knowledge. Ontology languages are usually declarative languages, are almost always generalizations of frame languages, and are commonly based on either first-order logic or on description logic.

Classification of ontology languagesEdit

Classification by syntaxEdit

Traditional syntax ontology languagesEdit

Markup ontology languagesEdit

These languages use a markup scheme to encode knowledge, most commonly with XML.

Controlled natural languagesEdit

Open vocabulary natural languagesEdit

Classification by structure (logic type)Edit


Three languages are completely or partially frame-based languages.

Description logic-basedEdit

Description logic provides an extension of frame languages, without going so far as to take the leap to first-order logic and support for arbitrary predicates.

Gellish is an example of a combined ontology language and ontology that is description logic based. It distinguishes between the semantic differences among others of:

  • relation types for relations between concepts (classes)
  • relation types for relations between individuals
  • relation types for relations between individuals and classes

It also contains constructs to express queries and communicative intent.

First-order logic-basedEdit

Several ontology languages support expressions in first-order logic and allow general predicates.

See alsoEdit


  1. ^ Kuhn, Tobias. "Attempto Controlled English as ontology language." REWERSE Annual Meeting. 2006.
  2. ^ www.executable-english.com