Content designation:
Content designation refers to the codes and conventions (tags, indicators, subfield codes and coded values) established explicitly to identify and further characterize the data elements within a record and to support the manipulation of that data. The content designation is defined by each of the USMARC formats.
Within variable data fields, two kinds of content designation (or designators) are used: indicator positions and subfield codes.
For more information on content designators, including indicators and subfield codes, select: