Searching vocabularies: a developing category of online search tools

Vocabularies such as thesauri and lists of subject headings have tended in the past to have been regarded as ‘indexing vocabularies’ rather than ‘searching vocabularies.’ Online searching, which requires input of search terms before any part of the database can be scanned, and which usually permits searching on ‘free’ terms as well as controlled terms, has placed emphasis on the need for vocabularies for searching. The term ‘searching vocabularies’ has been used to describe vocabularies produced with the searcher, rather than primarily the indexer, in mind. Such vocabularies are categorized as: enhanced thesauri and lists of subject headings, term listings, synonym listings and merged vocabularies.