What are "Boolean operators?" If you search a catalog or database and receive a very large number of results, adding or limiting an additional keyword can help narrow your results and make your searches more useful. Boolean operators refer to the words "AND," "OR," and "NOT" (in capital letters) used in searches to either narrow or expand search results.
For example, a search for Japan AND literature will return items that contain both concepts:
poetry OR performance returns items that contain either one of the concepts or both:
Japan NOT China returns items that talk about Japan but do not mention China: