0 Coleman, Anita Dervos, Dimitris 2006 Knowledge organization for a global society : Proceedings of the Ninth International ISKO Conference, 4-7 July, Vienna , Austria 51-58 data,definitions,information,metadata Many competing definitions for the terms data, information, metadata, and knowledge can be traced in the library and information science literature. The lack of a clear consensus in the way reference is made to the corresponding fundamental concepts is intensified if one condiders additional disciplinary perspectives , e.g. database technology, data mining, etc. In the present paper, we use a common sense approach, to selectively survey the literature, and define these terms in a way that can advance the interdisciplinary development of information systems.