The collection 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}. Every knowledge base, knowledge-based system, or knowledge-level agent is committed to some ConCeptualisation, explicitly or implicitly. (1994-10-19)