A method of combining concepts in a search that allows the searcher to make use of three logical commands: AND -- Narrows or limits the results by adding two or more terms together. OR -- Broadens or expands the results by including related terms. NOT -- Prevents unwanted records in a search by excluding a term or topic. Some nice examples at Boolean Searching from SUNY-Albany Libraries and at Boolean Searching Help from Library of Congress.
Search strategy that allows combining of terms. Terms are combined using 'operators' such as “AND”, “OR”, “NOT”. “AND” requires that all terms must appear in the record. “OR” retrieves records with either all or some of the terms. “AND NOT” is used to exclude terms from a search. Parentheses ( ) may be used to groups words/terms.
A search method developed by the 19th century English mathematician George Boole. It is based on the concept that the keywords in a search can be linked by three logical operators: AND, OR and NOT. An “and” search narrows the topic by adding additional search terms that must be found in the search results (i.e. violence and children). An “or” search broadens the results by including anything that includes either term (i.e. children or adolescents). A “not” search limits the search by excluding unwanted terms (i.e. viruses not computer). More than one logical operator can be used for more precise search results (i.e. violence and children not television). See also: Logical operators, “And” search, Keyword searching, “Not” search, “Or” search, and Nesting.