Ontology language

Classification of ontology languages

Classification by syntax

Traditional syntax ontology languages

• Common Logic - and its dialects
• CycL
• DOGMA (Developing Ontology-Grounded Methods and Applications)
• F-Logic (Frame Logic)
• FO-dot (First-order logic extended with types, arithmetic, aggregates and inductive definitions)
• KIF (Knowledge Interchange Format)
  • Ontolingua based on KIF
• KL-ONE
• KM programming language
• LOOM (ontology)
• OCML (Operational Conceptual Modelling Language)
• OKBC (Open Knowledge Base Connectivity)
• PLIB (Parts LIBrary)
• RACER

Markup ontology languages

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

• DAML+OIL
• Ontology Inference Layer (OIL)
• Web Ontology Language (OWL)
• Resource Description Framework (RDF)
• RDF Schema (RDFS)
• SHOE

Controlled natural languages

• Attempto Controlled English

Open vocabulary natural languages

• Executable English

Classification by structure (logic type)

Frame-based

Three languages are completely or partially frame-based languages.

• F-Logic
• OKBC
• KM

Description logic-based

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.

• KL-ONE
• RACER
• OWL.

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-based

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

• Common Logic
• CycL
• FO-dot (First-order logic extended with types, arithmetic, aggregates and inductive definitions)
• KIF