Confusion often arises when different people use terms to mean different things. In drawing up the following list, the original authors of the Willpower Information website have expressed gratitude for suggestions and comments from three consultant colleagues who specialize in the development and use of thesauri and other forms of structured vocabulary for information retrieval: Stella Dextre Clarke, Alan Gilchrist, and Ron Davies.
An attempt was made to maintain consistency with current standards for controlled vocabularies.
A B C D E F G H I K L M N O P Q R S T V
a posteriori relationship
See syntagmatic relationship
a priori relationship
See paradigmatic relationship
array of terms
For thesaurus purposes, the word ‘array’ means (a) a set of sibling terms or (b) a subset of sibling terms grouped under a node label that specifies a characteristic of division.
authority file, authority list
A controlled vocabulary, generally of proper names, for use in naming particular entities consistently. Separate authority lists may be maintained for different entity types, for example, personal names, organization names, and geographical names. The format of names used in an authority file should be documented and preferably in accord with recognized standards. A personal and corporate name authority file might look like this:
British Tabulating Machine Company
merged into International Computers and Tabulators
Bill Gates
use for William Henry Gates
William Henry Gates
use Bill Gates
ICL
use International Computers Limited
ICT
use International Computers and Tabulators
International Computers and Tabulators
created by merger of British Tabulating Machine Company and Powers-Samas
subsequently International Computers Limited
International Computers Limited
formerly International Computers and Tabulators
Powers-Samas
merged into International Computers and Tabulators
Prime Computer Inc.
Science Museum (London). Library
Victory (ship)
browsing
Finding information by examining lists or sequences of items.
caption
Statement of the subjects represented by a notation in a classification scheme. A caption may have to be read in conjunction with its hierarchical context. It need not be as complete or as self-contained as a scope note, or even a preferred term in a thesaurus.
chain index
An index to a classification scheme in which entries are generated by successive left truncation of strings of terms representing compound concepts, e.g., in the example of citation order, a compound concept is represented by the pre-coordinated string.
bicycles - tires - punctured - repairing - instruction books
In a classification scheme arranged in this way, everything on bicycles will be grouped together, but material on tires or instruction books will be scattered. To provide index entries to allow these scattered topics to be found, the string is written in reverse order and successively truncated from the left. This results in an index entry for each resulting substring:
instruction books - repairing - punctured tires - bicycles
repairing - punctured tires - bicycles
punctured tires - bicycles
tires - bicycles
bicycles
These entries are then arranged in alphabetical order:
bicycles
instruction books - repairing - punctured tires - bicycles
punctured tires - bicycles
repairing - punctured tires - bicycles
tires - bicycles
Each of these index entries would be followed by the appropriate notation to link it to its place in the classification scheme. As the citation order of this classification determines that everything about tires for bicycles will be grouped together in the classified sequence, it is not necessary for the index to have entries such as tires - bicycles - punctured, or other combinations and permutations of the terms in the string. A chain index is thus more economical than a fully permuted index, in which a string of five terms would generate 120 index entries.
The mechanical method of generating a chain index described here may be modified by editorial intervention to suppress entries which are likely to be unsought, and to combine terms grammatically to make the index entries more readable.
characteristic of division
Attribute by which a concept can be subdivided into an array of narrower concepts each having a distinct value of that attribute. e.g., in the following, ‘number of wheels’ and ‘motive power’ are characteristics by which the concept of ‘vehicles’ is divided. These are shown in the node labels (vehicles by number of wheels) and (vehicles by motive power).
Concepts in an array of terms should be mutually exclusive, having distinct values of the characteristic of division, although lower-level concepts can occur under more than one.
citation order
The order in which preferred terms or notations are combined in a pre-coordinate indexing system or a classification scheme to form strings representing compound concepts. The choice of citation order determines which concepts are most important for grouping together in a catalog or list and increases consistency in the construction of strings for similar subjects.
Citation order is usually specified by the facets to which concepts belong or the roles that they play in relation to other concepts in the string. A sequence that is often appropriate, especially for technical subjects, is:
thing - kind - part - property - material - process - operation - system operated on - product - by-product - agent - space - time - form
e.g.,
|
bicycles |
- |
tires |
- |
punctured |
- |
repairing |
- |
instruction books |
|
(thing) |
- |
(part) |
- |
(property) |
- |
(operation) |
- |
(form) |
classification
Grouping together of similar or related things and the separation of dissimilar or unrelated things, and the arrangement of the resulting groups in a logical and helpful sequence. Classification is a backbone for organizing fields of knowledge and indexing.
classification scheme
A schedule of concepts arranged by classification. A classification scheme may also include an index.
classified display
Because of the subjects to which they relate, terms that represent concepts are brought together and displayed in a thesaurus structure. Such a display may contain sections ofhierarchical display but may also bring together related terms from different facets, such as the people, activities, and objects relating to a subject. Classified displays may include node labels containing facet names as well as node labels specifying characteristics of division. An example of a classified display is shown under node label.
coined term
A new term created to express a concept for which no suitable term exists in the required language.
collection
The set of documents that may be accessed by a structured vocabulary, whether the items in it are collected in one place or distributed over a network.
complex concept
A concept that combines two or more simple concepts. Complex concepts are sometimes expressed in a single word but are more often conveyed by a multi-word term.
concatenated terms
A sequence of preferred terms representing a compound concept in a pre-coordinate indexing system.
concept
A unit of thought. The semantic content of a concept, regardless of wording or language. Concepts exist in the mind as abstract entities that are independent of the terms used to label them.
concept scheme
A set of concepts, optionally including statements about semantic relationships between those concepts. Thesauri, classification schemes, subject heading lists, taxonomies, terminologies, glossaries, and other types of controlled vocabularies are all examples of concept schemes.
controlled vocabulary
A prescribed list of terms or headings, each one having an assigned meaning. Controlled vocabularies are designed for use in classifying or indexing documents and for searching them. They normally contain a unique preferred term for each concept or entity with links to that term from non-preferred terms. They may also show relationships between terms.
descriptor
See preferred term
document
An item that can be classified or indexed in order that it may be retrieved. This definition refers not only to written and printed materials in paper or microform versions (for example, books, journals, diagrams, maps), but also to non-printed media, machine-readable and digitized records, Internet and intranet resources, films, sound recordings, people, and organizations as knowledge resources, buildings, sites, monuments, three-dimensional objects or realia, and to collections of such items or parts of such items.
entry term
enumerative classification scheme
A classification scheme in which all the concepts available for use are listed in the schedules. Compare with synthetic classification scheme.
equivalence relationship
A relationship between two terms that both represent the same concept. When two or more such terms are in the same monolingual thesaurus, one of them is designated a preferred term and the other(s) non-preferred term(s); the relationship is known as intra-vocabulary equivalence. When both terms are preferred terms in different thesauri, the relationship is known as cross-vocabulary equivalence.
Facet, fundamental facet
A grouping of concepts of the same inherent category. Examples of categories that may be used for grouping concepts into facets are: activities, disciplines, people, materials, living organisms, objects, places, and times:
(1) animals, mice, daffodils, and bacteria could all be members of a living organisms facet.
(2) digging, writing, and cooking could all be members of an activities facet.
(3) Paris, the United Kingdom, and the Alps, could all be members of a places facet.
Categories are normally chosen so that facets are mutually exclusive; a concept cannot then occur in more than one facet. In a classification scheme, facets may be restricted to a single discipline, such as a diseases facet in medicine, or may be common facets such as people, time, place, and form, which apply across all disciplines. Facets may be subdivided into mutually exclusive subfacets.
Some writers use the term ‘facet’ to specify the role that a concept plays in a complex concept, as well as the category to which it belongs. For example, they may say that materials can belong to ‘raw materials’ or ‘products’ facets, and people may be in ‘agents’ or ‘patients’ facets. For clarity, it is better to avoid this usage, keeping the term ‘facet’ for fundamental categories such as ‘materials’ or ‘people’, and specifying roles separately. Both facets and roles are used in setting up rules for citation order.
Other writers use the term ‘facet’ to mean ‘attributes’ or ‘properties’, confusing them with characteristics of division. There may be multiple characteristics of division of concepts within a single facet, e.g., within a materials facet there may be a concept of wines, subdivided into several arrays, not mutually exclusive, each headed by a node label such as <wines by color>, <wines by sweetness>, <wines by origin>, <wines by price> and so on. Any specific wine can be listed in several of these arrays. Searching by these is better called searching by parameters or characteristics rather than by facets.
facet analysis
An analysis of subject areas into constituent concepts grouped into facets.
facet indicator
A notational device that indicates the start of a new facet within a synthesized compound classmark. Examples of facet indicators are the 0 in the Dewey Decimal Classification, and parentheses and quotation symbols in the Universal Decimal Classification. In the past the term facet indicator has been used as synonymous with node label but that usage should be avoided, to avoid confusion.
faceted classification scheme
A classification scheme in which subjects are analyzed into their constituent facets. Schedules are compiled for each facet, and terms or notations from these may be combined according to prescribed rules to express a complex concept.
folksonomy
A collection of terms allocated to resources by users in order to categorize or index them in a way that the users consider useful. Terms in folksonomies, often called tags, are typically added in an uncontrolled manner, without any underlying structure or principles. They may be idiosyncratic but may also use current terminology more quickly than it can be incorporated into a controlled and structured scheme. Consistent and widespread folksonomy tags may eventually be incorporated into controlled vocabularies as quasi-synonyms, synonyms or non-preferred terms.
fundamental facet
See facet
glossary
A list of terms, together with definitions, specific to a given field of knowledge, usually presented in alphabetical order.
hierarchical display
Display of a thesaurus structure based on broader/narrower concept relationships. In such a display narrower terms are commonly shown indented under the broader term which is their parent. Each hierarchy, starting from a ‘top term’ contains terms from only a single facet or subfacet, so node labels containing facet names do not occur within hierarchies, though they may be shown at the top of each. A hierarchical display may contain node labels specifying characteristics of division. An example of a hierarchical display is shown under characteristic of division.
homograph
One of two or more words that have the same spelling, but different meanings
e.g., The term bank, for example, could refer to a financial institution or the side of a river.
identifier
A specific term that is not included in a controlled vocabulary, but which may be assigned to a document because it is considered useful for retrieval. Identifiers are often proper names, trade names, codes, jargon, and specialized terms. They should be distinguished from controlled vocabulary terms by being recorded in a separate field of a catalog record or by being flagged in some way. Some computer systems assign a unique number or code to each concept or term for purposes of managing the vocabulary, and it may be known as a 'concept identifier', 'term identifier', or simply 'term ID'. This type of identifier should not be confused with the usage defined here.
indexing
Intellectual analysis of the subject matter of a document to identify the concepts represented in it and allocation of the corresponding preferred terms to allow the information to be retrieved. The term ‘subject indexing’ is often used for this concept, but within a context that does not deal with other elements such as authors or dates, ‘indexing’ is sufficient.
information retrieval
Systems, techniques, and software working in combination to identify, search, and retrieve information from document collections and data sets. With the World Wide Web linking an enormous number of databases and online libraries, retrieval has been empowered for the individual Web user through an evolving history of information classification/categorization approaches and data analysis trends.
What is meant by this term depends on the data storage system(s) and information architecture available through an access point, with retrieval usually mediated by a search engine.
interoperability
The ability of two or more systems or components to exchange information and to use the information that has been exchanged. Vocabularies can support interoperability by including relations to other semantic structures, by presenting data in standard formats, and by using systems that support common computer protocols.
keyword
A word occurring in the natural language of a document that is considered significant for indexing and retrieval, often extracted for use in a metadata subject/descriptor field. Compare to free text. (From the Z39.19 ANSI/NISO standard.)
lead-in term
loan term
A term borrowed from another language that has become accepted in the borrowing language, e.g., glasnost, gourmets.
mapping (process)
The process of establishing relationships between the terms, notations, or concepts of one vocabulary and those of another.
map (product of mapping process)
Statement of the relationships between the terms, notations, or concepts of one vocabulary and those of another.
metadata
Metadata refers to ‘data about data’ and provides (a) access points by which records of documents can be sorted or retrieved, and (b) descriptive, administrative or structural information, by which the relevance of a document can be assessed without consulting it in full. Preferred terms or notations selected during the indexing process are commonly applied as metadata elements to describe the subject of a document.
microthesaurus
Subset of a thesaurus, usually containing terms from a subject area narrower than the scope of the whole thesaurus. The UNESCO thesaurus is subdivided into seven microthesauri; the UK Archival Thesaurus, based on the UNESCO thesaurus, is also subdivided into microthesauri, which it calls ‘fields of knowledge’.
monohierarchical structure
A hierarchical arrangement of concepts, in a thesaurus or classification scheme, in which each concept can have only one broader concept. When a polyhierarchy is not desired or allowed within a controlled vocabulary, like terms are typically differentiated using parenthetical qualifiers, e.g., mercury (chemical element), Mercury (deity).
multilingual thesaurus
A thesaurus using more than one language, in which each concept is represented by a preferred term in each of the languages, and there is a single structure of hierarchical and associative relationships between concepts which is independent of language.
node label
A label inserted into a hierarchical or classified display to show how the terms have been arranged. A node label contains one of two different types of information: either (1) the name of a facet or subfacet to which following terms belong (this type would be better called a ‘facet label’, but unfortunately this usage is not established in the literature or standards); or (2) the attribute or characteristic of division by which an array of sibling terms has been sorted or grouped.
The following classified display starts with the facet ‘disciplines’ and changes of facet are shown by node labels of type 1, shown in parentheses. A node label of type 2 is shown in angle brackets:
photography
- (people)
- photographic models
- - <photographic models by gender>
- - female photographic models
- - male photographic models
- photographers
- (operations)
- taking photographs
- developing
- printing
- (objects)
- cameras
- photographs
- - black and white photographs
- - color photographs
non-preferred term, entry term, lead-in term
A term that is not assigned to documents but is provided as an entry point in a thesaurus or alphabetical index. A non-preferred term is followed by a reference to the appropriate preferred term or terms in a controlled vocabulary, e.g., hounds USE dogs.
notation
A symbol or group of symbols representing a simple or compound concept, to sort and/or locate concepts in a pre-determined systematic order, and optionally to display how concepts have been structured and grouped. Notation can provide the link between alphabetical and systematic lists in a thesaurus, and between the alphabetical index and classified sequence of a classification scheme.
e.g., partial schedule showing notation in the left-hand column:
P200 photography
P250 - - photographic equipment
P251 - - - camera accessories
P251.3 - - - - flash guns
P251.5 - - - - tripods
P253 - - - cameras and camera components
P253.1 - - - - camera components
P253.13 - - - - - camera lenses
P253.15 - - - - - camera viewfinders
P253.2 - - - - cameras
notation system
A set of symbols, with rules for combining them to create notations for concepts. This set may be any selection of numerals, upper and lower case alphabetic characters, and punctuation symbols. The larger the set of symbols on which the notation is based, the greater the number of concepts that can be represented by distinct notations of the same length.
Punctuation marks may be used in notations:
1. to show relationships between concepts, e.g., 53:61 "physics in relation to medicine";
2. to act as facet indicators, showing that the subsequent symbols refer to a concept from a different facet, e.g., 61(94) "medicine in Australia";
3. to show where the notation may be abbreviated if desired, e.g., ; 641.5'68, "cooking for special occasions", may be abbreviated to 641.5, "cooking";
4. to break up long strings to make them easier to read, e.g., the period and spaces in 635.977 138 9 "fertilizers for flowering trees" or KVQ EOM MUR "unemployment in rural communities in India".
one-to-many mapping
mapping in which a single term, notation, or concept in one vocabulary is represented by two or more terms, notations, or concepts in another vocabulary
one-to-one mapping
mapping in which a single term, notation, or concept in one vocabulary is represented by a single term, notations or concepts in another vocabulary
The representations in the two vocabularies may or may not be identical.
ontology
Specification of the concepts of a domain and their relationships, represented in a computer-readable format. As the nature of relationships can be specified as part of the ontology, many more types of relations are possible than in a thesaurus. Ontology permits naming and description of a specific associative relationship, e.g., Poet <is writer of> Poetry.
Ontology is a form of classification that facilitates the indication of specific functional relationships among terms in a given context.
orphan term
A preferred term that has no hierarchical relationships.
paradigmatic relationship, a priori relationship, semantic relationship
Relationship between concepts which is inherent in the concepts themselves. Such relationships are shown in a structured vocabulary, independently of any indexed document.
parametric searching
Searching for concepts with specific values of characteristics of division e.g., searching for wines for which the color is red and the alcohol content is from 5% to 10%.
This type of search is for concepts that occur within one or more arrays of a single facet, e.g., narrower terms of wine in a ‘materials’ facet grouped under the node labels (wine by color) and (wine by alcohol content). In some systems it is possible to search for a range of values rather than just for specific values.
It is to be distinguished from searches for compound concepts that may be made up of concepts from different facets, such as wine from a ‘materials’ facet combined with red color and alcohol content from a ‘properties’ facet.
polyhierarchical structure
A hierarchical arrangement of concepts in a thesaurus or classification scheme in which each concept can have more than one broader concept.
Compare with monohierarchical structure. In a polyhierarchical structure, a single concept can occur at more than one place in the hierarchy. Its attributes and relationships, and specifically its scope note and its narrower and related terms, are the same wherever it occurs.
post-coordinate indexing
A system of indexing in which the subject of a document is analyzed into its constituent concepts by an indexer, but the preferred terms so allocated are not combined until they are selected by a user at the search stage.
When using post-coordinate indexing, a manual on bicycle repair might be assigned the three separate preferred terms
· bicycles
· repairing
· instruction books
Someone searching for such a manual would compose a search statement such as (bicycles AND repairing AND instruction books). The document would also be retrieved by a search for (bicycles AND instruction books) or for any one or more of the preferred terms. Compare pre-coordinate indexing.
precision
Measure of retrieval performance defined by R/T, where R is the number of relevant items retrieved and T is the total number of items retrieved.
pre-coordinate indexing
A system of indexing in which the preferred terms allocated to a particular document are syntactically combined in one or more sequences representing the only combinations available for retrieval purposes.
When using pre-coordinate indexing, a manual on bicycle repair might be assigned the indexing string made up of three preferred terms in combination:
bicycles - repairing - instruction books
This brings all aspects of repairing bicycles together in a catalog or browsing list, and might be followed by
bicycles - repairing - tools
There would be no direct alphabetical access to this subject under repairing, instruction books, or tools. This does not mean that the individual concepts within a pre-coordinated string cannot be searched for separately, either as controlled preferred terms or as free text, but such methods are not part of the pre-coordinate indexing system. Compare post-coordinate indexing.
preferred term, descriptor
A term specified by a controlled vocabulary for use to represent a concept when indexing, e.g., schools; school uniform; costs of schooling; teaching. A preferred term should preferably be a noun or noun phrase.
quasi-synonym
Apart from their ordinary distinctive meaning and usage, one of two or more terms that may be treated as labels for the same concept within a given controlled vocabulary, e.g., diseases, disorders; earthquakes, earth tremors.
recall
A measure of retrieval performance defined by R/N, where R is the number of relevant items retrieved, and N is the total number of relevant items.
scope note
A note which defines or clarifies the meaning of a concept as it is used in the structured vocabulary. A preferred term used to label a concept may have several meanings in normal usage. A scope note may restrict the concept to only one of these meanings and may refer to other concepts that are included or excluded from the scope of the concept being defined.
search thesaurus
A vocabulary intended to assist searching even though it has not been used to index the documents being searched. Search thesauri are designed to facilitate choice of terms and/or expansion of search expressions to include terms for broader, narrower, or related concepts, as well as synonyms. Optionally, a normal thesaurus may be used as a search thesaurus.
semantic network
Actual or virtual graphical representation of concepts and the relationships between them.
A semantic network is a way of representing an ontology. The vertices of the network represent concepts, and the edges represent semantic relationships between them. The vertices are sometimes called ‘nodes’, which are not to be confused with the node labels of a thesaurus or a faceted classification.
semantic relationship
See paradigmatic relationship
sibling term
One of two or more terms with the same immediate broader term. For example, in the following, biology, chemistry, geology, and physics are sibling terms. So are nuclear physics and quantum physics.
sciences
- biology
- chemistry
- - analytical chemistry
- geology
- physics
- - nuclear physics
- - quantum physics
source vocabulary
Language or vocabulary that serves as a starting point when seeking a corresponding term in another language or vocabulary. When working with two vocabularies, the source vocabulary for one concept may be the target vocabulary for another concept.
specificity
Capability of a structured vocabulary to express a subject in depth and in detail.
Specificity has an important influence on retrieval performance, as it determines the accuracy with which concepts may be pinpointed and consequently, the facility to exclude unwanted documents.
string
A sequence of preferred terms representing a compound concept in a pre-coordinate indexing system.
structured vocabulary
A set of terms, headings, or concept codes and their inter-relationships which may be used to support information retrieval. A structured vocabulary may also be used for other purposes. In the context of information retrieval, the vocabulary should be accompanied by rules for how to apply the terms.
subfacet
A subdivision of a facet, based on inherent categories. Subfacets, like facets, should be defined so that they are mutually exclusive. For example, an ‘agents’ facet might be subdivided into ‘individuals’ and ‘organizations’ subfacets; an ‘activities’ facet might be subdivided into transitive ‘actions’ and intransitive ‘processes’ subfacets.
Some writers use the term ‘subfacet’ as synonymous with array, or with the slightly broader meaning of the whole subtree of concepts grouped under a node label showing a characteristic of division, rather than just the first level array of sibling terms. Leonard Will has suggested that it should not be used with these meanings, as the intuitive meaning is ‘a subdivision of a facet’, and we already have the terms ‘array’ and ‘subtree’ for the other meanings.
subject heading list
subject heading scheme, subject heading list
A controlled vocabulary comprising single terms available for subject indexing, plus rules for combining the single terms in strings. The principles for constructing subject heading lists differ from the principles of thesaurus construction. Subject heading lists may have provision for the construction of pre-coordinated indexing strings including headings and one or more levels of subheading.
synonym
One of two or more terms whose meanings are considered identical in a wide range of contexts. Abbreviations and their full forms may be treated as synonyms, e.g., HIV, human immunodeficiency virus; guarantees, warranties.
synonym ring
A group of terms that are considered equivalent for the purposes of retrieval.
Synonym rings are particularly useful in search thesauri, used for searching unindexed material, where a search for any one of the terms in the ring can retrieve occurrences of any of the terms in the ring. No single term in a synonym ring is designated as preferred over others, unlike in a controlled vocabulary.
syntactic relationship
syntagmatic relationship, a posteriori relationship, syntactic relationship
Relationship between concepts that exists only because they occur together in a document being indexed. Such relationships are not generally valid in contexts other than the document being indexed, and therefore they do not form part of the structure of a thesaurus.
synthetic classification scheme
A classification scheme in which users can synthesize terms or notation for complex concepts from lists of simpler concepts. Compare with enumerative classification scheme.
target vocabulary (also see mapping and maps)
Language or vocabulary in which a term is sought corresponding to an existing term in a source language or vocabulary. When working with two vocabularies, the target vocabulary for one concept may be the source vocabulary for another concept.
taxonomy
A monohierarchical classification of concepts, as used, for example, in the classification of biological organisms. "In information management, a grouping of terms representing topics or subject categories. A taxonomy is typically structured so that its terms exhibit hierarchical relationships to one another, between broader and narrower concepts." Taxonomy structure is discussed in the ANSI/NISO Z39.19 (2005, re-affirmed 2010) standard.
term
Word or phrase used to label a concept: terms in a thesaurus can be either preferred terms or non-preferred terms.
thesaurus
A type of controlled vocabulary in which concepts are represented by preferred terms, placed in context by defining a variety of relationships among the thesaurus terms. As with most taxonomies, thesauri define broader and narrower term relationships (hierarchical relationships). In addition, they specify related terms (associative relationships) that allow the user to identify conceptual relationships among different term groupings. One more type of term relationship in thesauri is the synonym relationship or equivalence relationship, which establishes preferred and non-preferred terms.
These three – the hierarchical, associative, and equivalence relationships – work together to enrich a thesaurus and make it far more than a simple word list, basic controlled vocabulary such as an authority list, or a strictly hierarchical taxonomy.
top terms
Terms in a hierarchical vocabulary having narrower terms or branches but no broader terms.
topic map
A concept scheme conforming to the specification given in the international standard ISO/IEC 13250, Topic maps.
ISO/IEC 13250 gives the following three definitions for ‘topic map’:
a) A set of information resources regarded by a topic map application as a bounded object set whose hub document is a topic map document conforming to the SGML architecture defined by this International Standard.
b) Any topic map document conforming to the SGML architecture defined by this International Standard, or the document element (topicmap) of such a document.
c) The document element type (topicmap) of the topic map document architecture.
The introduction to ISO/IEC 13250 says: "In general, the structural information conveyed by topic maps includes:
- groupings of addressable information objects around topics ('occurrences'), and
- relationships between topics ('associations')".
vocabulary control
Restriction of choice of indexing terms to those in a specified list. This restriction increases the likelihood of indexers and searchers choosing the same term to label a concept.
Consult Access Innovations’ Information Science Glossary for additional terms and definitions not found here.
Original material from which this page is derived, © Willpower Information, 2008-2013