In searching and database querying, logical operators are often used to describe the desired data. For example, the query cat OR dog will return all documents that contain the word cat as well as all documents that contain the word dog.
logical operator. (2006). In High definition: A-Z guide to personal technology. Houghton Mifflin. Credo Reference: http://ezproxy.dbq.edu:2048/login?qurl=https%3A%2F%2Fsearch.credoreference.com%2Fcontent%2Fentry%2Fhmhighdef%2Flogical_operator%2F0%3FinstitutionId%3D4075
Performing the search in the catalog is the easiest way to demonstrate this.