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In this section, you will find information about the structure and syntax that informs the Thesaurus for Graphic Materials.
TGM I is a thesaurus in alphabetical format. As stated previously, TGM I conforms to the ANSI standard for structure and syntax. "Postable" terms (terms that are authorized for indexing) and "non-postable" terms (cross references pointing from unauthorized to authorized terms) are interfiled. Under each authorized term, the reference structure includes unauthorized terms (UF), broader terms (BT), narrower terms (NT), and related terms (RT). For each relationship that is established in the thesaurus, its reciprocal relationship can be found at another point in the thesaurus.
Example: Building dedications (authorized term)
UF Dedication of buildings (term not authorized)
BT Dedications (broader authorized term)
NT Church dedications (narrower authorized terms)
Cornerstone laying
RT Buildings (related authorized terms)
Groundbreaking ceremonies
Toppings out
Dedication of buildings
USE Building dedications (cross reference from unauthorized term to authorized term)
Used for (UF): A term that is not authorized for indexing. UF terms are listed primarily for editorial purposes, but they may help searchers by clarifying the scope or meaning of a term. The reciprocal is USE.
Use (USE): A cross reference that points catalogers and searchers to an authorized term. USE references may be made from synonyms, near synonyms, antonyms, inverted phrases, or other closely related terms or phrases. The reciprocal is UF.
Broader term (BT): An authorized term which indicates the more general class to which a term belongs. Everything that is true of a term is also true of its broader term(s).
Narrower term (NT): An authorized term which is narrower in scope and a member of the general class represented by the broader term under which it is listed. The reciprocal is BT.
Related term (RT): An authorized term which is closely related to the term under which it is listed, but the relationship is not a hierarchical one. The reciprocal is also RT.
Although no precise rules dictate when related term references should be supplied, some typical situations include:
TGM I tends to be generous in supplying related term references. This is partly because relationships that would be implicit in a hierarchical display of the terms are less apparent when the terms appear in an alphabetical display. In accordance with thesaurus construction guidelines, however, related term references are never made to two terms at different levels in the same hierarchy.
Example:
Game industry NOT Game industry
RT Games RT Games
Board games
[a narrower term to Games]
More detailed definitions and discussion of hierarchical and related term relationships can be found in the ANSI standard.
In accordance with the ANSI standard, terms are selected based on common usage and are established using natural language word order and modern American spelling conventions.
Headings for concrete concepts are established in the plural:
Example: Theaters
Watermelons
Headings for abstract concepts are established in the singular:
Example: Civilization
Headings for activities are established as gerunds:
Example: Banking
Running
Compound terms are established (1) when a single concept is expressed by multiple words in natural language, (2) when it would be difficult or unnecessary for an indexer to differentiate between two closely related concepts, and (3) when splitting them into single terms to be placed in separate fields would lead to retrieval of irrelevant material.
Example: Artificial flowers
Cattle ranches
Educational organizations
Real estate development
Tobacco industry
Compound terms are always expressed in natural language order, never inverted:
Example: Protestant churches NOT Churches, Protestant
Compound terms which include the word "and" are used when two terms occur together with such frequency that it would be undesirable to establish them separately. Such terms are constructed with an ampersand (&) in order to differentiate in retrieval systems between the use of "and" as a Boolean operator and the use of "&" as part of an indexing term:
Example: Doors & doorways
Good & evil
Qualifiers are used to differentiate between homographs.
Example: Camouflage (Biology)
Camouflage (Military science)
Facet indicators, which appear in brackets directly underneath authorized terms, signal that a term may be subdivided by geographic and/or nationality designations.
Example: Military camps
--[nationality]--[country or state]--[city]
These indicators have been included on a systematic basis with certain categories of headings; with other types of headings, they are added as need arises in P&P's cataloging. (See Section III for further information about using geographic, nationality, and other types of subdivisions.)
TGM I uses several kinds of notes to help catalogers apply terms consistently and to help researchers find appropriate search terms.
The public note (PN) defines a term, explains its scope, or helps a user understand the structure of the thesaurus.
Example: Bison
PN For the American buffalo. Search under BUFFALOES
for buffaloes of the eastern hemisphere.
The cataloger's note (CN) clarifies how to use a term or when to use it in conjunction with another term ("double indexing").
Example: Sick bays
CN Double index under type of vessel.
The note "TGM II term," which occurs frequently throughout TGM I, refers to terms which also appear in Thesaurus for Graphic Materials II: Genre and Physical Characteristic Terms. (See Section II.E. for guidance on application of these terms.)
Example: Stereographs
CN TGM II term.
Notes beginning with the phrase "Used in a note under ..." are of value primarily in editing and maintaining the thesaurus.
Example: Doves
CN Used in a note under SYMBOLS.
The history note (HN) records the fact that a change has taken place in a term or the status of a term since the publication of the first edition of TGM I. This may prove useful to searchers since it suggests terms that may have been in use formerly and that should be checked to retrieve older catalog records. Generally, if one term has been completely replaced by another term, the older term appears as a "UF."
Example: Draft
HN Changed 11/1987 from COMPULSORY MILITARY SERVICE.
The thesaurus maintenance software (LEXICO) used to produce TGM I follows ASCII filing rules. Thus,