Knowledge organization system (KOS), concept system or concept scheme is the generic term used in
knowledge organization for the selection of concepts with an indication of selected semantic relations.[1] Despite their differences in type, coverage and application, all KOS aim to support the organization of knowledge and information to facilitate their
management and
retrieval.
Hodge, G. (2000). Systems of Knowledge Organization for Digital libraries. Beyond traditional authority files. Washington, DC: the Council on Library and Information Resources.
http://www.clir.org/pubs/reports/pub91/contents.html
Zeng, M. L. & Chan, L. M. (2004). Trends and issues in establishing interoperability among knowledge organization systems. Journal for the American Society for Information Science and Technology, 55(5), 377-395.