The glossary gives definitions for terms used in the MARC 21 Format for Classification Data.  When the term is used in connection with a specific field(s), the content designator to which it applies is in parentheses at the end of the definition.  If a term applies only to a particular classification scheme (Library of Congress Classification or Dewey Decimal Classification), it is so indicated.

 

-A-

add or divide like instructions.  Instructions to the classifier to construct a classification number by adding numbers from other parts of the schedule, from a table, or by basing it on a pattern defined in another part of the schedule.  (761; 763; 765)

 

-B-

base number.  Classification number to which one or more other numbers are appended or added by applying a table or other add or divide like instructions.  (761; 763; 765)

 

-C-

caption.  A heading that corresponds to a classification number or span and describes the subject covered.  (153; 453; 553)

caption hierarchy.  The caption(s) corresponding to classification number(s) at succeeding levels of the classification hierarchy.  Each element in the caption hierarchy describes a more general topic than the caption itself.  See also caption; hierarchy.  (153; 453; 553)

centered entry (DDC).  A classification number span and its corresponding caption representing a subject covered by a summary span of numbers.

class elsewhere tracing (DDC).  A tracing that instructs the user to class parts of a class or topics related to it in the number(s) in the 153 field rather than the number(s) in the tracing field.  (553)

classification scheme.  A logical system for the arrangement of knowledge.  A fully developed classification scheme specifies categories of knowledge and provides the means to relate the categories to each other and to specify in the classification number all or the most important of the aspects and facets of a subject.  (084)

complex reference.  A reference note that leads the user from the number in the 153 field to the number in the reference note field when the relationship cannot be adequately conveyed by one or more simple cross references generated from a 453 or 553 tracing field.  (253; 353)

controlled index term.  An index term intended to supplement index terms derived from data in the MARC record that is controlled by subject access terms based on a thesaurus or authority file.  See also uncontrolled index term.  (700; 710; 711; 730; 750; 751; 754)

 

-D-

defined number span.  A range of classification numbers that is defined by a separate table or subarrangement.  See also number span; summary number span.

 

-E-

external table.  A table that has a special designation and is intended to be applied to numbers within the classification scheme.  For MARC classification data, each entry in the table is contained in a separate record.  See also table; internal table.

 

-F-

facet.  Any of the various categories into which a given class may be divided, e.g., division of the class "people" by the categories race, age, education, language spoken, and so on.

 

-H-

heading (DDC).  See caption.

hierarchical force (DDC).  The principle that the attributes of a class that are defined in the heading and in certain basic notes apply to all the subdivisions of the class and to all other classes to which reference is made.  (680)

hierarchical level.  The degree of specificity within a section of the classification scheme.  In the Dewey Decimal Classification, the hierarchical level is indicated by the length of the notation and the corresponding depth of indention of the heading in a class.  In the Library of Congress Classification, the hierarchical level is determined by the number of indentions of the caption under the subclass, which indicates its degree of specificity.

hierarchy.  The arrangement of a classification scheme from general to specific.

 

-I-

index.  A list of terms appended to a classification schedule intended to provide subject access to classification numbers within the scheme.  (700-75X)

internal table.  A table that appears within the classification schedule that specifies an internal classification subarrangement or a set of tabulated numbers found in add notes under specific numbers.  It refers to a specific and limited part(s) of the schedule and does not have a table designation.  For MARC classification data, each entry in an internal table is contained in a separate field within a classification record.  See also table; external table.  (763)

invalid classification number.  A classification number that cannot be used in a bibliographic or authority record.  Generally it refers to the number to be used either in a simple tracing or a complex reference.  (008/08; 253; 453)

 

-M-

machine-assisted classification.  An online expert system designed to guide library classifiers to the correct classification number for the topic.

 

-N-

number building.  See synthesized number.

number span.  A range of classification numbers with a beginning and ending number.  See also defined number span; summary number span.

 

-O-

obsolete classification number.  A classification number associated with a caption that was once valid but is no longer.  (008/08; 685)

optional classification number (DDC).  An officially recognized optional variation on the standard classification number, as specified in the classification schedule.  (008/09; 683)

 

-R-

root number (DDC).  The initial digits of a pattern number or span when these digits are not added.  (761; 763; 765)

 

-S-

schedule.  The series of numbers, captions and accompanying instructions or notes that constitute the core of a classification scheme.  For the Library of Congress Classification, the schedules are designated from A-Z with one, two, or three letters denoting the class or subclass within the schedule.  In the Dewey Decimal Classification, the schedules are designated by the series of DDC numbers 001-999.

scheme.  See classification scheme.

standard subdivision do-not-use tracing (DDC).  A tracing that instructs the classifier not to add the standard subdivisions in Table 1.  Standard subdivisions represent frequently recurring physical forms (dictionaries, periodicals) or approaches (history, research) applicable to any subject or discipline.  (253; 453; 553)

summary number span.  A range of classification numbers that summarize a topic or topics.  For the Dewey Decimal Classification, see also centered entry.  (008/07)

synthesized number.  A number that has been made appropriately specific by adding or appending numbers from a table or from other parts of the schedule.  (008/12; 761; 763; 765; 768)

 

-T-

table.  A table of numbers that may be added to other numbers in the schedules to make a class number appropriately specific to the work being classified.  Table numbers cannot stand alone.  If a table appears internally within the schedule, intended to be applied to a limited group of classification numbers, it may be considered an internal table or subarrangement and recorded in field 763 (Internal Subarrangement or Add Table Entry).  Alternatively, a classification agency may consider an internal table an external one for purposes of coding.  See also external table; internal table.

table of preference (DDC).  A special type of internal table indicating which one of two or more numbers is to be chosen when the numbers represent different characteristics of a subject that cannot be shown in full by number building.  (768)

tracing.  A number that leads directly to another number.  A simple cross reference display is generated from a tracing field.  The tracing is located in the record for the number to which it refers.  See also complex reference.  (453; 553)

 

-U-

uncontrolled index term.  An index term intended to supplement index terms derived from data in the MARC record that is not controlled by subject access terms based on a thesaurus or authority file.  For instance, it may provide any additional terms not appearing in the classification data record, such as synonyms, commonly used terms, see references.  See also controlled index term.  (753)

 

-V-

valid classification number.  A classification number that may be used in a bibliographic or authority record either by itself or with additional letters or numbers.  In the case of a number span, a portion of it may be used in a bibliographic or authority record.  It may be valid for the particular edition of the classification scheme, as designated in field 084 (Classification Scheme and Edition).  See also invalid classification number.

See also:

Appendices