The Neuchatel Group is an informal co-operation between the statistical offices of Denmark, Norway, Sweden and Switzerland to clarify some basic concepts and to arrive at a common terminology for classifications. The first meeting of the Group was held in Neuchatel, Switzerland in June 1999. The meeting resulted in a draft Neuchatel Terminology document and a tentative conceptual model, in which the object types of a classification database, and the attributes connected with each object type, are listed an described.