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Work with WebDewey records

Learn how to work with WebDewey records, including how to use associated LC subject headings, associated terms from DDC Relative Index, and cross-references.

Record elements

  • Each record represents an entry in the DDC schedules or tables or a built number synthesized according to instructions in the schedules and/or tables.
  • Each record contains a DDC number, a caption (heading) describing the class (subject) that the number represents, a representation of the class number’s position in the DDC hierarchy, and term(s) from the DDC Relative Index.
  • Records often include one or more notes explaining the correct application of the class number.
  • Records include terminology associated with the number from Library of Congress subject headings and/or MESH headings.
  • If a DDC number can be segmented (i.e., truncated at a logical break), the segmented form of the number is shown at the top of the record, immediately below the class number or table number.

Record details

Element Description
DDC Number See the following table DDC number types for details.
  • For each DDC number in the schedules, tables, and manual, a caption (heading) defines the subject or subdivision that number represents. For built numbers, the caption given is the first Relative Index term (in alphabetic order) associated with that number. Therefore, if a built number contains more than one Relative Index term, note all the Relative Index terms associated to it; all associated Relative Index terms can apply to that number, not merely the alphabetically first Relative Index term associated to the built number in its caption.
  • Footnoted captions. Captions preceded by an asterisk, dagger, and/or double dagger contain footnotes. In most cases, footnotes explain how to create a more specific class number by adding notation.
  • Captions with ellipses. Captions that end with ellipses occur only in records for built numbers. Built numbers do not appear in the DDC schedules but are constructed according to add instructions stated or implied in the schedules or tables. WebDewey uses the associated Relative Index term as the caption for a built number. If multiple Relative Index terms are associated with a built number, the first term in alphabetical order appears as the caption, followed by ellipses. (Ellipses, which also appear in browse results, indicate that more than one Relative Index term is associated to a given built number.)
  • Below the caption, each WebDewey record contains a representation of the number’s position in the DDC hierarchy. Records for manual entries do not contain a hierarchy display.
  • The hierarchy display shows the selected number, the hierarchy of broader class numbers that contain it (up to the main class or the table introduction record), and the first level of narrower classes subordinate to it.
  • One or more numbers in the hierarchy display will end in zero(s) that appear in bold text. The bold zeros indicate levels in the DDC hierarchy. Two bold zeros indicate that a number belongs to the top level of the DDC hierarchy: the 10 main classes, or first summary. One bold zero indicates that a number belongs to the 100 divisions, or second summary. Three-digit numbers in which all digits appear black belong to the 1,000 sections, or third summary.
  • A built number appears in a hierarchy only when it is the subject of the record or is parallel to the subject of the record. Built numbers never appear in the upward or downward portions of hierarchies for other class numbers.
  • A WebDewey record may contain one or more notes. Notes serve the following purposes:
    • Describe what is found in the current class. Such notes may define the class, clarify its scope, give examples of subjects that belong in the class, or indicate where interdisciplinary and comprehensive works are classed.
    • Identify topics with standing room in the number where the note is found. Standing room numbers provide a location for topics with relatively few works written about them, but whose literature may grow in the future, at which time they may be assigned their own number.
    • Describe related topics found in other classes. Such notes may list topics to be classed elsewhere in the DDC, or provide See or See Also references. In WebDewey, cross references include hyperlinks to the referenced record. Click the linked DDC number to view the cited record.
    • Explain changes or irregularities in the schedules or tables. Such notes may identify a revised, discontinued, or relocated class or instruct classifiers not to use the current number.
  • Some WebDewey records contain a link labeled Segmentation Instruction in the Notes field. Segmentation instructions explain how to segment numbers that you build. This information is generally needed only by national libraries and other large agencies.
  • If you have created comments associated with a DDC record, they appear in an area labeled Comments.
  • To edit a user note associated with the DDC record you are viewing, click the Edit button.
  • For information on creating and editing comments, see Create and edit comments.
Terminology Sources
  • Most records for schedule numbers and built numbers contain terms from the DDC Relative Index and Library of Congress subject headings associated with the class numbers. Most records for manual numbers contain terms from the DDC Relative Index.
  • Records may contain terms from one additional source: MESH.
  • Each record includes boxes for all possible terminologies and any associated terms are listed automatically. To hide a term list, click the down-arrow button next to the source name.
Relative Index Terms
  • Terms from the DDC Relative Index name the topics covered by the number in the record.
  • Many Relative Index terms have subheadings (preceded by two hyphens) that indicate the discipline in which the topics are treated in the class represented by the number.
LC Subject Headings
  • Associated Library of Congress subject headings appear in records for most schedule numbers and built numbers.
  • The headings are hyperlinked to subfield $a of the heading field in the corresponding LC subject authority record.
MeSH Terms National Library of Medicine subject headings associated with the DDC class number in the record.


DDC number types

Number type Example Description
Class number 004.67 Number or span of numbers provided in the DDC schedules to represent a subject.
Built class number B 598.176 A number constructed according to add instructions stated or implied in the schedules or tables to represent a specific subdivision of a DDC class.
Centered entry C 930-990 Represents a subject covered by a span of numbers.
Optional number (921) Number enclosed in parentheses; a class number that is an optional alternative to the number usually assigned to a concept.
Bracketed number [104] Unassigned 511[.22] Intuitionistic mathematics [291] Comparative religion T5--[04] Persons of mixed ancestry with ethnic origins from more than one continent Number enclosed in square brackets; a number that has been discontinued or relocated, or an unassigned number. Record instructs you not to use this number and provides a cross-reference to the correct class number.
Table number T1--071 Number for an entry in one of the DDC numbered auxiliary tables (Tables 1–6; in the Abridged Edition, Tables 1–4). Provides notation that can be added to other numbers to make a class number appropriately specific to the work being classified.
Built table number T4--092 A number constructed according to add instructions stated or implied in the schedules or tables to represent a specific subdivision of a DDC table.
Table centered entry T2--4- T2--9 Number used to indicate and relate structurally a span of table numbers that together form a single concept.
Add table notation 617:028 Number for an entry in one of the DDC add tables (lists of special notation found in add notes under specific numbers throughout the schedules and occasionally in Tables 1–6). What precedes colon is class number or span where add table is located; what follows colon is notation to be added. Provides notation that can be added to other numbers, as instructed at the beginning of the add table, to make a class number appropriately specific to the work being classified.
Manual number M 361-365 A number or range of numbers covered in an entry in the DDC Manual. The manual entry explains the proper use of the class number (or range).


Use associated LC subject headings

  1. In the WebDewey record, scroll down to view the Terms section or click the Terms button.
  2. Under LC Subject Headings, find the heading(s) applicable to the item you are classifying.
  3. Click the hyperlinked heading to display the LC subject authority record for the heading. The authority record appears in a new browser window.
  4. Review the authority record to verify that the heading is suitable for the bibliographic record you are creating/modifying.
  5. (Optional) Copy and paste the heading from the subject authority record to a bibliographic record.
    1. In the authority record, select the text of the heading. Right-click the text. On the popup menu, click Copy.
    2. In the main window, display the bibliographic record in a template edit view. Right-click in the field where you want to insert the heading. On the popup menu, click Paste.
    3. Control the heading. In the list, click Control Heading.

Use associated terms from DDC Relative Index

The Relative Index terms associated with a WebDewey record provide an at-a-glance view of other terminology associated with a class number.

Use cross-references

The Notes section of the WebDewey record may include cross-references to related class numbers, table numbers, instructions, or manual entries within WebDewey.

To follow a cross-reference, click the hyperlinked DDC number. If the cited record is for a manual entry, it appears in a new browser window; otherwise, the hyperlinked record replaces the record in the current browser window.