A subject heading is a word or phrase, which describes or represents a concept or topic.
Most subject headings are common, everyday words.
People, places, and organizations may also be used as subject headings. If you want to read a book about Alice Walker, the author of The Color Purple , you search under Walker, Alice as a subject heading. Problems occur when people use different words to describe a subject. Dismissal, firing or termination would all be valid. These subject headings, used by the Library of Congress since 1989, are published in four red books which can be found on the table in the Reference Center.