A controlled vocabulary is an established list of standardised terminology for use in indexing and retrieval of information. The list must be conceived as a structured list of descriptors explicitly enumerated. Each descriptor is a preferred term with an unambiguous and non-redundant definition, controlled by and available from a controlled vocabulary registration authority. Descriptors in a controlled vocabulary can have hierarchical, equivalent or associative relations. A controlled vocabulary is managed by an authority, which can be a thesaurus manager or a centralized organization responsible for managing the vocabulary. Controlled vocabularies allow a standardized way of indexing collections in a local database or online catalogue. It is also a powerful tool for web search queries and for sharing data on the web. Glossaries, thesauri, classification systems/taxonomies and subject headings, ontologies, are types of controlled vocabularies. They are also referred to as authority lists.

Explore further the Linked Heritage learning object: Terminology.