SUBJECT SUBDIVISION

These are words or phrases that can follow a subject heading, and are listed below the subject heading and indicated by a dash. These words or phrases are used to make the subject more specific. Subdivisions may be topical, a physical form indicator, a geographical indicator, or chronological.

Below is part of a page from the LCSH, showing some of the subdivisions for the City of Boston, Massachusetts. (Library of Congress Subject Headings, 24th edition, p. 747.) Valid subdivisions are marked in bold letters. Primary subdivisions are preceded by a single dash. Secondary subdivision—that is subdivisions of subdivisions are preceded with a double dash. For subdivisions that are not to be used, the acceptable subdivision is given. For example instead of using the subdivision "Description" the cataloger is told to use "Description and travel." We will discuss more about this shortly.

Bostock family
     USE Bostick family
Bostocke family
     USE Bostick family
Boston (Mass.)
     — Description
              USE Boston (Mass.)—Description and
                        travel
    — Description and travel
             UF Boston (Mass.)—Description
                      [Former heading]
    — Garrison mob, 1835
             USE Garrison Mob, Boston, Mass.,
                        1835
    — History
               [F73]
    — — Colonial period, ca. 1600-1775
    — — Siege, 1775-1776
                   BT Sieges—Massachusetts
    — — Revolution, 1775-1783
                  NT Boston Port Bill, 1774
                        Boston Tea Party, 1773
     — — Antislavery movement, 1830-1863
                  USE Antislavery movements—
                             Massachusetts—Boston
    — — Civil War, 1861-1865
    — — 1865 -
    — Police Strike, 1919
             USE Police Strike, Boston, Mass.,
                        1919