150 Heading - Topical Term (NR) (Variable Data Field)

Field definition and scope:

Field 150 contains a topical term used as a heading in an established heading record , an established heading and subdivision record , a traced or an untraced reference record , a reference and subdivision record , or a node label record . In an established heading record, field 150 contains the established form of a topical term. In records for references and node labels, this field contains an unestablished form of a topical term.

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

Field 150 is NOT repeatable .

Guidelines for applying content designators:

The content designators identify the subelements occurring in topical term and node label headings constructed according to generally accepted thesaurus-building conventions (e.g., Library of Congress Subject Headings).

Topical terms include occupation and function terms that are used as the lead element of subject or added entry access fields in bibliographic records.

A topical term that is authorized for use only as a subject subdivision part of an extended subject heading is contained in a 180 (General Subdivision) or 182 (Chronological Subdivision) field.

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

See: Examples for this field.

Input conventions:

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

Punctuation

Spacing

Display constant

Content designator history:

Second Indicator - Nonfiling characters [obsolete]: The second indicator position was made obsolete in fields 150, 450, and 550 in 1993. The values were: 0-9 (Number of nonfiling characters present).

LC guidelines for usage:

150 Heading - Topical Term

Related MARC field or document:

X50 Topical Terms - General Information

See also:

1XX Headings

Variable Data Fields