650 Subject Added Entry

Field definition and scope:

Field 650 contains a topical subject used as a subject added entry.

Subject added entries are assigned to a community information 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).

Field 650 is repeatable.

Guidelines for applying content designators:

For indicator and subfield code definitions and examples, and designator repeatability, see table below:

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

Second	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 code:
$a	Topical term or geographic name as entry element	NR
$b	Topical term following geographic name as entry element	NR
$v	Form subdivision	R
$x	General subdivision	R
$y	Chronological subdivision	R
$z	Geographic subdivision	R
$0	Authority record control number or standard number	R
$1	Real World Object URI	R
$2	Source of heading or term	NR
$3	Material specified	NR
$6	Linkage	NR
$8	Field link and sequence number	R

Input conventions:

Content designator history:

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

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

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