Gellish is a formal language that is natural language independent, although its concepts have 'names' and definitions in various natural languages. Any natural language variant, such as Gellish Formal English is a controlled natural language. Information and knowledge can be expressed in such a way that it is computer-interpretable, as well as system-independent and natural language independent. Each natural language variant is a structured subset of that natural language and is suitable for information modeling and knowledge representation in that particular language. All expressions, concepts and individual things are represented in Gellish by (numeric) unique identifiers (Gellish UID's). This enables software to translate expressions from one formal natural language to any other formal natural language.
Gellish is a universal and extendable conceptual data modeling language. Because it includes domain-specific terminology and definitions, it is also a semantic data modelling language and the Gellish modeling methodology is a member of the family of semantic modeling methodologies.
Gellish started out as an engineering modeling language ("Generic Engineering Language", hence the name, "Gellish") and was subsequently developed into a language with general applications.
Gellish is intended for the expression of facts (statements), queries, answers, etc. For example, for the complete and unambiguous specification of business processes, products, facilities and physical processes; for information about their purchasing, fabrication, installation, operation and maintenance; and for the exchange of such information between systems, although in a system-independent, computer-interpretable and language independent way. It is also intended for the expression of knowledge and requirements about such things.
The definition of Gellish can be derived from the definition of Gellish Formal English by considering 'expressions' as relations between the Unique Identifiers only. The definition of Gellish Formal English is provided in the Gellish English Dictionary-Taxonomy, which is a large 'smart dictionary' of concepts with relations between those concepts (earlier it was called STEPlib). The Dictionary-Taxonomy is called a 'smart dictionary', because the concepts are arranged in a subtype-supertype hierarchy, making it a taxonomy that supports inheritance of properties from supertype concepts to subtype concepts. Furthermore, because together with other relations between the concepts, the smart dictionary is extended into an ontology. Gellish has basically an extended object-relation-object structure to express facts by relations, whereas each fact may be accompanied by a number of auxiliary facts about the main fact. Examples of auxiliary facts are author, dates, status, etc. To enable an unambiguous interpretation Gellish includes the definition of a large number (more than 650) of standard relation types that determine the rich semantic expression capability of the language.