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Short Description

A Definition is a text that helps parties to have the same understanding about the meaning of a term, and hence enables communications. The quality of a definition is the extent in which parties can use it to actually demonstrate that they have the same understanding.

The problem that definitions (as we see them) contribute to solving is misunderstandings that may arise as every party has its own knowledge and autonomously determines the semantics it uses to express itself in texts/speech/pictures, and interpret that of other parties. The fact that the semantics of parties is subjective makes it realistic to assume that the meaning that a party intends to convey as it expresses itself is not the same as how another party interprets that expression - a 'misunderstanding'.

All parties have learned, with varying degrees of sophistication, to identify misunderstandings, and ways to recover from that.

A common mechanism for reducing the likelihood of misunderstandings to occur, is to associate terms with texts that are crafted to help parties have the same understanding, i.e. definitions. This mechanism is sometimes overrated in the sense that definitions are often considered to be universally valid rather than only useful in specific scopes.

Therefore, we insist that such texts

  • are associated with a scope within which they are considered to be valid/useful (for the objectives that parties pursue in that scope);
  • are phrased as a criterion that every such party can evaluate so as to determine whether or not something qualifies to be referred to by that term. The quality of such texts is the extent in which parties reach the same conclusion as they evaluate the criterion in an arbitrary use-case that is relevant for the scope.

The terminology pattern provides an overview of how this concept fits in with related concepts. The eSSIF-Lab terminology process provides guidance for making and maintaining quality definitions. Practical guidance is provided by the report "On Terminology, and the Resolution of Related Issues".


Working together is easier when you and your peers share the same ideas. We need a way to test and ensure, that you and your peers actually have the same understanding, for the purpose of making cooperation easier. Doing so is expected to not only reduce the number of terminological discussions, but also improve the efficiency and effectiveness of the remaining discussions.


A definition is a text that comprises at a minimum:

  • a scope that is curated (controlled) by a party, and that is related to (the pursuit of) a non-empty set of objectives;
  • a criterion that specifies the necessary and sufficient conditions for determining what does and what does not constitute some concept (idea, class of entities);
  • a name or phrase that is used within the scope to refer to (unidentified, or arbitrary, or specific) entities that satisfy the criterion.


  • The definition of the term definition (a) is defined in, and hence valid in the scope eSSIFLab, (b) specifies a criterion (see the Criteria section above), and (d) has a name (i.e. definition) associated with it. Since it satisfies the criteria of definition, it can be referred to as 'the definition of definition'.
  • The concepts defined within the scope eSSIFLab have definitions associated with them, where the criteria, relevance and terms are defined in the concept-file of that concept.
  • Term is a label that is used in some context to refer to a Concept, the set of entities that satisfy the concept's criteria, or an arbitrary element of that set. Different contexts may use different terms to refer to a single concept. In a single context, a single term should be used to refer to an individual concept.
  • Scope is related in several ways. First, there is (precisely, or at most one) Scope that governs the definition/specification of the Concept. Second, there may be (any number of) Scopes that use the Concept, i.e. within which Terms are defined that refer to the Concept
  • Mental(or Conceptual) Model is a collection of concepts, relations between such concepts, and constraint rules that (elements of) such concepts and relations must satisfy. Such [models]( are used to help people know, understand, or simulate a topic that the model represents.


Note that this definition satisfies itself. Also note that a definition may be used in multiple scopes, where a scope that wants to use the definition that has been defined in another scope, may replace that name with one of its own choosing. This way the meaning expressed by the definition remains preserved.

You may want to create definitions that are both acceptable for business people (for whom it usually suffices that they get the gist of it) as for engineers (that need much more precision, up to the point where they can use it for formal reasoning). You face the challenge of conveying your intangible ideas or concepts with tangible words or phrases. You can do this by using intensional definitions, i.e. by defining criteria that specify the necessary and sufficient conditions for when the term you define should (not) be used. When defining such criteria, make sure they have the following properties:

  • you are convinced that the vast majority of people in your audience will make the same judgements as you do when applying these criteria in a situation that you and your audience consider relevant; and
  • the ability to make this distinction is relevant for one or more purposes of your intended audience.

Note that the actual word or phrase you choose as the term name for a concept is much less important than the criteria you define. If in a particular context another name would be more suitable, you can define another term for that other context (scope) that still refers to the concept you created the definition for.

The Terminology Corpus provides templates that help you do that. The report On Terminology, and the Resolution of Related Issues provides further practical guidance for establishing and maintaining unambiguous and relevant terminology.

As a final note we would like to mention a quote of Confucius: "The whole end of speech is to be understood."