Answered By: Sarah Mailloux
Last Updated: Oct 22, 2015     Views: 18

Boolean operators  are words to broaden or narrow a search in electronic databases or any search engine. They can connect your search terms to find exactly what you're looking for.


  • The three basic boolean operators are: ANDOR, and NOT. In Internet search engines, math symbols such as + and - work the same way.
  • Using quotation marks "" and parentheses () keeps your search terms together when you have more than one search term.

For example:

"Milky Way" could mean either the candy bar or the galaxy.

By itself, "milky way" returns about 7,920,000 results. When you require the search engine to find more terms by using AND, fewer results will be returned:

"milky way" AND "candy bar"= About 144,000 results

Using OR should increase the number of results:

"milky way" OR "candy bar" should return results about the Milky Way galaxy, the Milky Way candy, or any other kind of candy: About 11,500,000 results 

If you need to learn more about the Milky Way galaxy without the distraction of candy, use NOT:

"Milky Way" NOT candy

Because search engines will look for all of the terms you type, try to stay away from commonly used words (a, an, the, in, of, on, are, be, if, into, which) unless they are important to your search: "balance OF payments" "Out OF Africa"

The library catalog and databases as well as internet search engines all contain an "advanced search" option that will help you to focus your search.

If you need more help finding sources for your topic, Ask a Librarian or call the library at 307.268.2269. We'd be happy to help!


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