657 Index Term - Function

Field definition and scope:

Field 657 contains index terms that describe the activity or function of the community information entity if such information is not already indicated in another 6XX field.

Standard lists are used for the function terms and the list is identified in subfield $2 (Source of term).

Field 657 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 657	Index Term - Function	R
Indicator:
First	Undefined; contains a blank

Second	Source of term
7	Source specified in subfield $2

Subfield code:
$a	Function	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 term	NR
$3	Materials specified	NR
$6	Linkage	NR
$8	Field link and sequence number	R

Input conventions:

Punctuation

Spacing

Display constant

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]