| First Indicator | Second Indicator |
|---|---|
| Undefined # - Undefined |
151 - Undefined # - Undefined 451 - Preferred variant heading # - No information provided 1 - Preferred variant heading 551 - Undefined # - Undefined 751 - Thesaurus 0 - Library of Congress Subject Headings 1 - Library of Congress Children's and Young Adults' Subject Headings 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 | |
|---|---|
|
Name portion
Control subfields
|
Subject subdivision portion
|
Content designators identify the subelements occurring in geographic name headings constructed according to generally accepted cataloging and thesaurus-building conventions (e.g., Anglo-American Cataloguing Rules (AACR2), Library of Congress Subject Headings). Jurisdiction names (including those that are ecclesiastical entities) alone or followed by subject subdivisions are X51 geographic names. A corporate name, a form subheading, a title of a work, and/or a city section name entered under the name of a jurisdiction are contained in the X10 fields. Geographic names used in phrase subject headings (e.g., Iran in the Koran) are contained in the X50 fields. A geographic name that is authorized for use only as a subject subdivision part of an extended subject heading is contained in a 181 (Geographic Subdivision) field.
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 451 and 551) and the 7XX Heading Linking Entries-General Information section (for field 751).
First Indicator - Undefined
Undefined and contains a blank (#).
Second Indicator - Preferred variant heading [451]
Preferred variant heading in an alternate language and/or script to indicate relative importance compared to other variants in the same language and script to guide use in discovery, display, etc. Only one 4XX field may be marked as "preferred” for each language and script. When identifying a preferred variant, the language and script should be identified using at least one method, such as a BCP47 language tag in $7.
| 151 | ##$aFlorida | ||||||||
| 451 | #1$aΦλοριντα$7(bcp47)el | ||||||||
| 451 | #1$aФлорида$7(bcp47)bg$7(bcp47)mk$7(bcp47)ru$7(bcp47)uk | ||||||||
| 451 | #1$aᎠᏟᏲᎷᎲᏍᎩᎢ$7(bcp47)chr-cher | ||||||||
| 451 | #1$a플로리다$7(bcp47)ko-hang | ||||||||
| 451 | #1$aᑉᓘᕇᑖ$7(bcp47)iu-cans | ||||||||
Second Indicator
In fields 151 and 551, the second indicator position is undefined and contains a blank (#). For field 751, the second indicator position contains one of the values described in the 7XX Heading Linking Entries-General Information section.
$a - Geographic name
Parenthetical qualifying information is not separately subfield coded.
| 151 | ##$aAmazon River | ||||||||
| 151 | ##$aCommunist countries | ||||||||
| 151 | ##$aHalley's comet | ||||||||
| 151 | ##$aInterstate 70 | ||||||||
| 151 | ##$aMason and Dixon's Line | ||||||||
| 151 | ##$aHimalaya Mountains | ||||||||
| 151 | ##$aIrrawaddy Division (Burma) | ||||||||
| 151 | ##$aLeesville (S.C.) | ||||||||
| 151 | ##$aPalenque Site (Mexico) | ||||||||
| 151 | ##$aPompeii (Extinct city) | ||||||||
| 151 | ##$aAltamira Cave (Spain) | ||||||||
| 151 | ##$aAntietam National Battlefield (Md.) | ||||||||
| 151 | ##$aGreenwich Village (New York, N.Y.) | ||||||||
| 151 | ##$aKing Ranch (Tex.) | ||||||||
| 151 | ##$aWarm Springs Indian Reservation (Or.) | ||||||||
| 151 | ##$aDelaware Memorial Bridge (Del. and N.J.) | ||||||||
$g - Miscellaneous information
Data element that is not more appropriately contained in another defined subfield.
| 151 | ##$aAugsburg$gRegion$xMONICA$gProjekt | ||||||||
| 151 | ##$aMichelbach$gAlzenau, Unterfranken$xApostelgarten$gLage, Weinbau [Examples in German of different types of entities with repeatable subfields $g.] |
||||||||
$i - Relationship information [451/551/751]
Designation of a relationship of the entity in a 451, 551, or 751 field to the 1XX entity in the record or a textual reference instruction phrase. For fields 451 and 551 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 451, 551, and 751. Guidelines for using subfield $i in fields 451 and 551 are provided in the Tracings and References-General Information section. Guidelines for using subfield $i in field 751 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 $v is appropriate in the X51 fields only when a form subject subdivision is added to a geographic name to form an extended subject heading.
| 151 | ##$aParis (France)$vGuidebooks | ||||||||
| 151 | ##$aRussia$xTerritorial expansion$vMaps, Pictorial | ||||||||
$w - Control subfield [451/551/751]
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 451, 551, and 751. Character position definitions and guidelines for applying the codes defined for subfield $w in field 451 and 551 are provided in the Tracings and References-General Information section. Character position definitions and guidelines for field 751 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 $x is appropriate in the X51 fields only when a topical or form subject subdivision is added to a geographic name to form an extended subject heading.
| 151 | ##$aTexas$xOfficials and employees$xPayroll deductions | ||||||||
| 151 | ##$aAix-en-Provence (France)$xSocial life and customs | ||||||||
| 151 | ##$aUnited States$xCommerce | ||||||||
$y - Chronological subdivision
Subject subdivision that represents a period of time. Subfield $y is appropriate in the X51 fields only when a chronological subject subdivision is added to a geographic name to form an extended subject heading.
| 151 | ##$aGreece$xHistory$yGeometric period, ca. 900-700 B.C. | ||||||||
| 151 | ##$aUruguay$xHistory$yGreat War, 1843-1852 | ||||||||
| 151 | ##$aUnited States$xHistory$yCivil War, 1861-1865$xConscientious objectors | ||||||||
$z - Geographic subdivision
Appropriate in the X51 fields only when a geographic subject subdivision is added to a geographic name to form an extended subject heading.
| 151 | ##$aUnited States$xBoundaries$zCanada | ||||||||
$0 - Authority record control number or standard number [551/751]
See description of this subfield in Appendix A: Control Subfields.
$1 - Real World Object URI [551/751]
See description of this subfield in Appendix A: Control Subfields.
$2 - Source of heading or term [751]
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 751. Guidelines for applying subfield $2 are provided in the 7XX Heading Linking Entries-General Information sections.
$4 - Relationship [451/551/751]
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 451 and 551 are provided in the Tracings and References-General Information section. Guidelines for using subfield $4 in field 751 are provided in the 7XX Heading Linking Entries-General Information section.
$5 - Institution to which field applies [451/551/751]
See description of this subfield in Appendix A: Control Subfields.
$6 - Linkage
See description of this subfield in Appendix A: Control Subfields.
$7 - Data provenance
See description of this subfield in Appendix H: Data Provenance Subfields.
$8 - Field link and sequence number
See description of this subfield in Appendix A: Control Subfields.
Ambiguous Headings - See Appendix D: Ambiguous Headings.
Punctuation - Punctuation of the subelements of a heading is generally dictated by descriptive cataloging or subject heading system/thesaurus rules. These input conventions clarify MARC punctuation practices. An X51 field does not end with a mark of punctuation unless the field ends with an abbreviation, an initialism, or data that ends with a mark of punctuation.
| 151 | ##$aCambridge (Mass.)$xPopulation | ||||||||
| 151 | ##$aEgypt$xHistory$yTo 332 B.C. | ||||||||
| 151 | ##$aUnited States$xEconomic policy$y1981-1993 | ||||||||
| 451 | ##$wnnaa$aChino Valley, Ariz. | ||||||||
| 151 | ##$aChina$xHistory$yHan dynasty, 202 B.C.-220 A.D.$vBibliography | ||||||||
Spacing - No spaces are used in initialisms.
| 151 | ##$aWashington (D.C.) | ||||||||
| 151 | ##$aChina$xHistory$yHan dynasty, 202 B.C.-220 A.D. | ||||||||
One space is used between preceding and succeeding initials if an abbreviation consists of more than a single letter.
| 151 | ##$aVienna (W. Va.) | ||||||||
| 151 | ##$aAdelaide Geosyncline(S. Aust.) | ||||||||
| 151 | ##$aUnited States$xForeign relations$y1993-$vPeriodicals | ||||||||
Display Constant
| - | [dash associated with the content of subfield $v, $x, $y, and $z] |
Dash (-) that precedes a subject 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 subfield $v, $x, $y, and $z.
|
Content designated field:
|
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| 151 | ##$aUnited States$xBoundaries$zCanada | ||||||||
|
Display example: United States-Boundaries-Canada |
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Values were: 0-9 (Number of nonfiling characters present).
Indicator 2 was undefined between 1993-2026.
City section name entered under the name of a jurisdiction is contained in an X10 field. Records created before this change may contain an X51 field with a subfield $b for this type of name.
Subfield $4 was renamed and redescribed to allow for the recording of relationship URIs in addition to MARC and non-MARC codes.