Glossary

Broader term
The superordinate term in a hierarchical relation.
BT
A symbol used in a thesaurus to identify the following terms as broader terms to the heading term.
Chain
A sequence of terms in which the class represented by each term includes all the classes represented by the terms that follow that term.
Controlled indexing
Indexing with terms from a controlled vocabulary, such as a thesaurus.
Enumerative
Of an indexing or classification scheme, listing or enumerating terms explicitly, rather than making provision for synthesizing them.
Equivalent term
A term in a controlled vocabulary, such as a thesaurus, that is treated as if it means the same thing as another term.
Extraction indexing
Indexing with terms from the text or title of the item indexed.
Hierarchical relation
A semantic relation in which one term is strictly subordinate to the other; for example, a genus/species relation.
Homograph
A term with the same spelling as, but a different meaning from, another term.
Narrower term
The subordinate term in a hierarchical relation
Non-preferred term
A term in a controlled vocabulary, such as a thesaurus, that may not be used as a controlled indexing term, but may be looked up.
NT
A symbol used in a thesaurus to identify the following terms as narrower terms to the heading term.
Postcoordination
The combination of terms at the time of retrieval to form a compound search specification that corresponds to no single index term used in indexing.
Precision ratio
The ratio of the number of relevant items retrieved to the total number of items retrieved.
Precoordination
The combination of terms or other components to form compound terms at or before the time of indexing.
Preferred term
A term in a controlled vocabulary, such as a thesaurus that may be used as a controlled indexing term.
Quasi-synonym
An equivalent term that is not a synonym.
Recall ratio
The ratio of the number of relevant items retrieved to the total number of relevant items indexed.
Related term
A term in a semantic relation, but not in a hierarchical relation, to another term.
Relevant
Appropriately retrieved in response to a given query.
RT
A symbol used in a thesaurus to indicate that the following terms are related terms to the heading term.
Scope note
A note attached to a term in a controlled vocabulary, such as a thesaurus, that gives guidance on how to use the term.
Semantic relation
A relation between terms that is true as a matter of general knowledge, rather than depending on what the terms refer to in some particular document.
SN
A symbol used in a thesaurus to indicate that what follows is a scope note to the heading term.
Syntactic relation
A relation between terms that depends on what the terms refer to in some particular document, rather than being true as a matter of general knowledge.
Synthetic
Of an indexing or classification scheme, making provision for the synthesis of terms out of components, rather than listing or enumerating them explicitly.
Thesaurus
A device for vocabulary control, usually for a specific subject area, indicating preferred terms, non-preferred terms, and semantic relations between terms; the terms are in ordinary human language.
UF
A symbol used in a thesaurus to indicate that the following term or terms are not used in indexing and that the heading term is used instead.
USE
A symbol used in a thesaurus to indicate that the heading term is not used in indexing and that the following term or terms are used instead.

Introduction
Last updated January 25, 2008, by Tim Craven
Copyright © 1997 The University of Western Ontario