The process or result of listing the types of objects, concepts and other entities that are assumed to exist in some area of interest and the relationships that hold among them. A conceptualisation is an abstract, simplified view of the world that we wish to represent. For example, we may conceptualise a family as the set of names, sexes and the relationships of the family members. Choosing a conceptualisation is the first stage of knowledge representation. A conceptualisation is a high-level data model. Every knowledge base, knowledge-based system, or knowledge-level agent is committed to some conceptualisation, explicitly or implicitly.