What is the difference between controlled vocabularies, thesauri, classifications, ontologies?
A “controlled vocabulary” is a way to insert an interpretive layer of semantics between the term entered by the user and the underlying database to better represent the original intention of the terms of the user. Controlled vocabularies aid in collation of distributed data by providing a semantically understood and shared concept. For example, if all the resource * types* are taken from a controlled list, one can provide all the “Audio” resources by searching only those marked with Type=Audio. A “thesaurus” is “The vocabulary of a controlled indexing language, formally organized so that the a priori relationships between concepts (for example as “broader” and “narrower”) are made explicit” (ISO 2788, 1986:2). “A controlled set of terms selected from natural language and used to represent, in abstract form, the subjects of documents” (ISO 2788, 1986:2) The term “ontology” has been used for a number of years by the artificial intelligence and knowledge representation community but is no
