What are subject terms?
We have learned that databases store data such as title of books or papers and its authors in fields. By specifying which fields are to be searched, we can find relevant records more efficiently.
Next, let's look at a method of searching unique to databases, that is important for finding records matching your topic. This method is searching using a field called "subject matter" which stores terms describing the contents of records.
Let's take another look at the search results detail screen of KOSMOS.
In this example, the term "Ozone layer depletion" is added as a term that describes the content of this book. This means that this book is about the depletion of the ozone layer. Using the "subject matter" field, we can now search for records by their contents.
For instance, when searching KOSMOS for books containing the term "ozone layer depletion" in their titles, there is only one hit. In such cases, by looking at the detail descriptions of the records, and redefining your search with the subject matter "ozone layer depletion" (in other words, doing a search for books written on environmental health), we now get six hits.
Searching by subject matter, we can find records with relevant contents even though the term is not included in their titles.
Generally, terms stored in the field representing contents are referred to as subject terms. Subject terms that can be used in databases are predetermined, and can be referenced in the list of keywords, thesauruses, list of subject matters or subject headings attached to databases.
Example of a thesaurus: From "NASA Thesaurus"