Knowledge organization systems: collections, registers, services

The article discusses the concept of knowledge organization systems. Collections and registers of knowledge organization systems, as well as terminological services used in library and information activities and reflected in the Basic Register of Thesauri, Ontologies and Classifications (BARTOC) are considered. A description of BARTOC is provided. The types of collections of knowledge organization systems are analyzed for various reasons. A historical outline of the development of relevant activities in Russia is given. The list of existing 129 registries with web addresses is provided.