The editions of Library of Congress Subject Headings (LCSH) are rich sources for tracking shifts and trends in terminology over the century.
Why? Because subject headings serve as standardized labels for indexing the contents of library materials and reflect societal concerns and the language generally used to express them. New subject headings are added to LCSH as the Library acquires materials about concepts and phenomena, and as catalogers recognize the need to identify those topics. A new heading "Aeroplanes" was handwritten into a copy of the 1898 edition of the American Library Association List of Subject Headings when LC began to acquire and catalog materials about that modern form of transport. "Refrigerators" was added as a heading in 1908. "Fascism" made its appearance in LCSH between 1928 and 1931, and "Radar" entered its scope in 1943. "Segregation in Education" was established as a heading in 1955 with "School integration" following in 1972. More recently "Internet (Computer Network)" became a heading in 1992 followed by "Internet Addiction" in 1998.
Today LCSH is enriched by contributions from an expanding pool of libraries that participate in the Subject Authority Cooperative Program (SACO). In 1996, the British Library proposed a subject heading "Road Rage" before American terminology had crystallized. That phrase has caught on in the United States while the phenomenon has increased.
Changing the form of a heading involves weighing the benefits of the change against the costs of carrying it out. During the era of the card catalog, a conservative approach was taken to changing headings because of the cost of revising catalog cards and then refiling them at the Library of Congress and elsewhere. Only in the 1970s were the outdated headings "Aeroplanes" and "Water-closets" updated to "Airplanes" and "Toilets." The replacement of the card catalog by an online catalog in the mid-1980s made changes easier to accomplish. A watershed of sorts was marked in 1987 when a decision was made to cancel the heading "Moving-pictures" in favor of "Motion Pictures," even though that change involved revising authority records for approximately 400 related headings and updating the subject headings assigned to thousands of catalog entries.
Sometimes headings that were originally established using formal or technical terminology are subsequently revised to reflect popular usage. In 1983 a subject heading for "Acquired Immune Deficiency Syndrome" was established after a telephone call to the Centers for Disease Control to verify that researchers had agreed on a standard name for that emerging disease. The heading was replaced with "AIDS (Disease)" in 1985, when the number of publications about the disease began to grow and awareness of it entered public consciousness. "Parabolic Antennas" was changed to "Satellite Dish Antennas" in 1997 after they had become more visible in the landscape.
Other recent heading changes include "Conjuring" to "Magic Tricks," "Children of Interracial Marriage" to "Racially Mixed Children," and "Parkinsonism" to "Parkinson's Disease."
