A limited hierarchy may be applied to allow for simple navigation, particularly when the authority file is being accessed manually or is extremely large. Examples of authority files include the Library of Congress Name Authority File and the Getty Geographic Authority File. A glossary is a list of terms, usually with definitions. The terms may be from a specific subject field or from a particular work. The terms are defined within a specific environment and rarely include variant meanings.
Dictionaries are alphabetical lists of words and their definitions.
Variant senses are provided where applicable. Dictionaries are more general in scope than are glossaries. While a dictionary may also provide synonyms and through the definitions, related words, there is no explicit hierarchical structure or attempt to group them by concept. A gazetteer is a list of place names. Traditional gazetteers have been published as books or have appeared as indexes to atlases.