representation of a concept by a descriptive statement which serves to differentiate it from related concepts
Note 1 to entry: A definition may be expressed as natural language text (a textual definition) or as a definition model. A textual definition should comply with the applicable guideline(s) in this standard. A definition expresses what is by definition the case for all things of the defined kind and if such an expressed constraint is not the case for a thing, then that thing is not a thing of the defined kind.
A definition model is a subtype of a knowledge model and consists of a number of expressions of facts about the defined concept. Those expressions should comply with the guidelines in this standard.[1]
1 Online Browsing Platform (OBP) [WWW Document], n.d. URL https://www.iso.org/obp/ui#search (accessed 4.10.21).