Abstract
The amount of work to be done in rendering the digital information space more efficient and effective has attracted a wide range of disciplines which, in turn, has given rise to a degree of confusion in the terminology applied to information problems. This note seeks to shed some light on the three terms thesauri, taxonomies and ontologies as they are currently being used by, among others, information scientists, AI practitioners, and those working on the foundations of the semantic Web. The paper is not a review of the techniques themselves.