| First Indicator | Second Indicator |
|---|---|
| Undefined # - Undefined |
155/455/555 - Undefined # - Undefined 755 - Thesaurus 0 - Library of Congress Subject Headings 1 - LC subject headings for children's literature 2 - Medical Subject Headings 3 - National Agricultural Library subject authority file 4 - Source not specified 5 - Canadian Subject Headings 6 - Répertoire de vedettes-matière 7 - Source specified in subfield $2 |
| Subfield Codes | |
|---|---|
|
Main term portion
Tracing and linking subfields
|
Subject subdivision portion
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Content designators identify the subelements occurring in genre/form term headings constructed according to generally accepted thesaurus-building conventions (e.g., Art & Architecture Thesaurus). Genre terms for textual materials designate specific kinds of materials distinguished by the style or technique of their intellectual contents; for example, biographies, catechisms, essays, hymns, or reviews. Form terms designate historically and functionally specific kinds of materials as distinguished by an examination of their physical character, characteristics of their intellectual content, or the order of information within them; for example, daybooks, diaries, directories, journals, memoranda, questionnaires, syllabi, or time sheets. In the context of graphic materials, genre headings denote categories of material distinguished by vantage point, intended purpose, characteristics of the creator, publication status, or method of representation.
Only generally-applicable content designators are described in full in this section. A small number of content designators with field-specific instructions are described in the Tracings and References-General Information section (for field 455 and 555) and the 7XX Heading Linking Entries-General Information section (for field 755).
First Indicator - Undefined
Undefined and contains a blank (#).
Second Indicator
In fields 155, 455, and 555, the second indicator position is undefined and contains a blank (#). For field 755, the second indicator position contains one of the values described in the 7XX Heading Linking Entries-General Information section.
$a - Genre/form term
May consist of more than one word.
| 155 | ##$aBird's-eye views$y1874 | ||||||||
| 155 | ##$aCartoons$y1952 | ||||||||
$i - Relationship information [455/555/755]
Designation of a relationship of the entity in a 455, 555, or 755 field to the 1XX entity in the record or a textual reference instruction phrase. For fields 455 and 555 the phrase may be system-generated from the field tag or from the codes defined for subfield $w (Control subfield). Subfield $i is appropriate only in fields 455, 555, and 755. Guidelines for using subfield $i in fields 455 and 555 are provided in the Tracings and References-General Information section. Guidelines for using subfield $i in field 755 are provided in the 7XX Heading Linking Entries-General Information section.
$v - Form subdivision
Designates a specific kind or genre of material as defined by the thesaurus being used. Subfield $v is appropriate only when a form subject subdivision is added to a genre/form term to form an extended heading.
| 155 | ##$aCartoons$vPeriodicals | ||||||||
$w - Control subfield [455/555/755]
Codes in one or more character positions defined to control the display of information and specify relationships, restrictions, and status. Subfield $w is appropriate only in field 455, 555, and 755. Character position definitions and guidelines for applying the codes defined for subfield $w in field 455 and 555 are provided in the Tracings and References-General Information section. Character position definitions and guidelines for field 755 are provided in the 7XX Heading Linking Entries-General Information section.
$x - General subdivision
Subject subdivision that is not more appropriately contained in subfield $v (Form subdivision), subfield $y (Chronological subdivision), or subfield $z (Geographic subdivision). Subfield $x is appropriate in the X55 fields only when a general topical subdivision is added to a main term to form an extended heading.
| 155 | ##$aDictionaries$xFrench$y18th century | ||||||||
$y - Chronological subdivision
Subject subdivision that represents a period of time. Subfield $y is appropriate in the X55 fields only when a chronological subject subdivision is added to the main term to form an extended heading.
| 155 | ##$aCompetition drawings$y1984 | ||||||||
$z - Geographic subdivision
Appropriate in the X55 fields only when a geographic subject subdivision is added to a main term to form an extended heading.
| 155 | ##$aHymnals$zMassachusetts$y18th century | ||||||||
$0 - Authority record control number or standard number [555/755]
See description of this subfield in Appendix A: Control Subfields.
$1 - Real World Object URI [555/755]
See description of this subfield in Appendix A: Control Subfields.
$2 - Source of heading or term [755]
Code that identifies the source of a heading or term when the second indicator position contains value 7. Subfield $2 is appropriate only in field 755. Guidelines for applying subfield $2 are provided in the 7XX Heading Linking Entries-General Information section.
$4 - Relationship [455/555/755]
Code or URI that specifies the relationship from the entity described in the record to the entity referenced in the field. Guidelines for using subfield $4 in fields 455 and 555 are provided in the Tracings and References-General Information section. Guidelines for using subfield $4 in field 755 are provided in the 7XX Heading Linking Entries-General Information section.
$5 - Institution to which field applies [455/555/755]
See description of this subfield in Appendix A: Control Subfields.
$6 - Linkage
See description of this subfield in Appendix A: Control Subfields.
$8 - Field link and sequence number
See description of this subfield in Appendix A: Control Subfields.
Punctuation - Term followed by a subject subdivision does not end with a mark of punctuation unless the preceding term ends with an abbreviation, initial/letter, open date, or other data that ends with in a mark of punctuation.
| 155 | ##$aPrayer books$zRhode Island$y18th century | ||||||||
Spacing - No spaces are used in initialisms, acronyms, or abbreviations.
Display Constant
| - | [dash associated with the content of subfield $v, $x, $y, and $z] |
Dash (-) that precedes a subdivision in an extended subject heading is not carried in the MARC record. It may be system generated as a display constant associated with the content of subfields $v, $x, $y, and $z.
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Content designated field :
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| 155 | ##$aAgenda$xWeekly$y1980-1985 | ||||||||
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Display example: Agenda-Weekly-1980-1985
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Prior to the definition of the X55 fields, X50 (Topical Terms) fields were used for genre/form headings.
Subfield $4 was renamed and redescribed to allow for the recording of relationship URIs in addition to MARC and non-MARC codes.