650 Subject Added Entry

Field definition and scope:

Field 650 contains a subject added entry in which the entry element is a topical term.

Topical subject added entries may consist of general subject terms including names of events or objects. Subject added entries are assigned to a bibliographic record to provide access according to generally accepted thesaurus-building rules [e.g., Library of Congress Subject Headings (LCSH), Medical Subject Headings (MeSH)]. Field 650 may be used by any institution assigning subject headings based on the lists and authority files identified in the second indicator position or in subfield $2 (Source of heading or term).

A title (e.g., Bible and atheism), a geographic name (e.g., Iran in the Koran), or the name of a corporate body (e.g., Catholic Church and humanism) used in a phrase subject heading are also recorded in field 650.

The National level record requirement for this field is Mandatory if applicable.

Field 650 is repeatable.

Guidelines for applying content designators:

The content designators identify the subelements occurring in topical subject and subdivisions and node labels.

For indicator and subfield code definitions and examples, National-level (NLR) and Minimal-level (MLR) record requirements, and designator repeatability, see table below:

Position	Description	NLR	MLR	Repeatability
Field 650	Subject Added Entry - Topical Term	A	O	R
Indicator:
First	Level of subject	M
#	No information provided	A
0	No level specified	A
1	Primary	A
2	Secondary	A

Second	Thesaurus	M
0	Library of Congress Subject Headings	A
1	LC subject headings for children's literature	A
2	Medical Subject Headings	A
3	National Agricultural Library subject authority file	A
4	Source not specified	A
5	Canadian Subject Headings	A
6	Répertoire de vedettes-matière	A
7	Source specified in subfield $2	A

Subfield code:
	Main term portion
$a	Topical term or geographic name entry element	M	O	NR
$b	Topical term following geographic name entry element	A	O	NR
$c	Location of event	A	O	NR
$d	Active dates	A	O	NR
$e	Relator term	A	O	R
$g	Miscellaneous information	A	O	R
$4	Relationship	O	O	R

	Subject subdivision portion
$v	Form subdivision	A	O	R
$x	General subdivision	A	O	R
$y	Chronological subdivision	A	O	R
$z	Geographic subdivision	A	O	R

	Control subfields
$0	Authority record control number or standard number	O	O	R
$1	Real World Object URI			R
$2	Source of heading or term	A	O	NR
$3	Materials specified	O	O	NR
$6	Linkage	A	O	NR
$8	Field link and sequence number	O	O	R

Input conventions:

Ambiguous headings (what is considered a "topical term")

Content designator history:

Subfield $b - Topical term following geographic name as entry element [restored]: Subfield $b was made obsolete in 1981. The subfield was restored for use in retrospective record conversion in 1987.

Subfield $g - Miscellaneous information [new, 2014]

Subfield $0 - Authority record control number [new, 2007]

Subfield $0 - Authority record control number [redefined, 2010]

Subfield $1 - Real World Object URI [new, 2017]

Subfield $4 - Relator code [new, 2005]

Subfield $4 - Relator code [renamed, 2017] [redescribed, 2017]: Subfield $4 was renamed to Relationship and redescribed to allow for the recording of relationship URIs in addition to MARC and non-MARC codes.