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Thesaurus for Graphic Materials II (TGM): An Introduction

III. Syntax and Structure

In accordance with thesaurus construction standards, terms usually represent single concepts and are plural nouns with phrases in natural language order. English words follow American spelling practice. The NISO thesaurus standard suggests that all homographs receive a qualifier to distinguish those words that have the same spelling and different meanings.


Thus, from the second edition on, the thesaurus terms include qualifiers; most were chosen by consensus in the Working Group on Form and Genre Vocabulary (WGFGV).1 More qualifiers are likely to be added as the WGFGV completes its review of terms.

The thesaurus structure is intended to help both catalogers and researchers select the term(s) most appropriate for indexing and retrieval. Terms appear in alphabetical order and are listed in word-by-word filing sequence. Scope notes (here called "public notes") define the terms in the context of the thesaurus. Associations between terms are indicated by the convention of broader, narrower, related, and "used for" relationships. Terms listed under a heading also appear in the alphabetical filing sequence with the reciprocal relationship noted. For example, the term EPHEMERA has LABELS listed as a narrower term, and the term LABELS has EPHEMERA listed as its broader term.

The difference between genres and physical characteristics may be unclear, for example, with terms like BROADSIDES, in which purpose is closely identified with one physical manifestation. The form-genre field (655) is to be used for the entire vocabulary.2

Notes and relationships:

PN: Public note - defines the scope of a term.

CN: Cataloger's note - guides indexers in selecting a term; for thesaurus maintenance, records other notes in which the term appears.

HN: History note - accounts for earlier ways in which a term appeared in the list, in particular, terms that formerly appeared as non-preferred (UF) terms; also, prompts the catalog user to search under earlier forms of headings, in case headings in a catalog have not been updated to the current forms.

Example:  Gem photographs: HN: Changed 5/89.  Formerly, Gem photographs may have been indexed as Miniature works.

UF: Used for - indicates a non-preferred term, such as an alternative spelling, inverted form, or synonym; helps define a term's meaning.

BT: Broader term - indicates the more general class to which a term belongs; everything that is true of a term is also true of its broader term.

NT: Narrower term - indicates a more specific term or member of a class.

RT: Related term - brings to the catalog user's attention terms that are associated because of overlapping meanings or part-whole relationships.

USE: leads from a non-preferred, unauthorized form of a term to the term as used.

+ : indicates that one or more narrower (i.e., more specific) terms will be found under this term's own entry. Appears only with NT terms, not RT terms.

The public note provides definitions for about 90% of the terms. The undefined terms are chiefly fine art or printmaking terms that can be found in commonly available dictionaries. The definitions have an American bias, particularly in the dates of popular usage and sizes that are cited. Most definitions have been modified to reflect their application within the context of this thesaurus; none should be considered too rigidly. The experimental techniques and subtle variations in many graphic processes preclude complete precision. The definitions are usually derived from several sources listed in the bibliography. Those based chiefly on one source mention the source, e.g., [AAT] for Art and Architecture Thesaurus.

While this thesaurus does not require facets to subdivide headings, such information may be added to a term to indicate where the cataloged material was made, when, and whether it is in color. General guidelines for subdivisions, as well as examples, are given in section V.6 of this introduction.

The Classed Display and Hierarchical Display, which appeared in the first edition, have been discontinued. They were not used enough to warrant their updating.


  1. In 1992, AAT director Toni Peterson and RBMS chair Laura Stalker received a Council on Library Resources grant to identify and resolve as many conflicting terms as possible through a Working Group on Form and Genre Vocabulary (WGFGV). Many thesauri were being constructed simultaneously in the 1980s. Despite efforts to use the same terminology, the resolution of conflicts was not always possible. The WGFGV participants represented: AAT, TGM II, Guidelines on Subject Access to Individual Works of Fiction, Drama, Etc. (GSA), LCSH Medical Subject Headings (MeSH), and RBMS. The reports of the 1992-1995 meetings are available from the AAT; the review work was concluded in 1995. Back to text
  2. The drawbacks that developed from having two fields (the 655 and the now-obsolete 755 field) are discussed in Jackie Dooley and Helena Zinkham, "The Object as 'Subject': Providing Access to Genres, Forms of Materials, and Physical Characteristics," in Beyond the Book: Extending MARC for Subject Access (Boston: G.K. Hall, 1990), 43-80. The first two (printed) editions of TGM II distinguished genre terms and physical characteristic terms with a "cataloger's note" specifying either the 655 or 755 field. When the 755 field was made obsolete this distinction was omitted from the online edition; the printed volume suggestions to use field 755 should be ignored. Back to text